Shadow the Hedgehog

Shadow the Hedgehog (シャドウ・ザ・ヘッジホッグ) is a fictional character from the Sonic the Hedgehog series. He is an anthropomorphic hedgehog/Black Arm hybrid and the arch-rival of Sonic the Hedgehog. Shadow was created as the "Ultimate Life Form" (究極生命体) by Gerald Robotnik, using the DNA of Black Doom, and is the end result of Project Shadow. His purpose was to provide ways to develop cures for incurable deadly illnesses, more specifically for Gerald's granddaughter Maria Robotnik, but he was captured and put into stasis by the military when he was deemed as a threat to humanity.

Fifty years later, Shadow was released by Dr. Eggman to help him conquer the world. Initially, Shadow sought to destroy the earth to avenge Maria, who had been killed by the military, but was persuaded to help save it from Gerald's doomsday plans. In the process, Shadow lost his memories and he sought to uncover his past, during which he met the Black Arms. Ultimately, Shadow thwarted Black Doom and saved the world. From there, Shadow continued his mission to protect humanity by becoming a special agent of GUN.

Shadow is sharp-witted, always on edge and has a strong sense of purpose, willing to accomplish his goals by any means. Essentially a dark version of Sonic, Shadow can match him in both speed and skill, and can use Chaos Control with a Chaos Emerald. While preferring to work alone, he has helped Sonic and his allies when needed.

Concept and creation
After the success of Sonic Adventure, it was only natural to assume that a sequel would be produced. Hoping that the game would be for the Dreamcast what Sonic the Hedgehog 2 was for the Mega Drive, a portion of the team responsible for the first Adventure title was sent off to work at Sega of America. It was led by director Takashi Iizuka, while Yuji Naka remained back in Japan to work on other properties, including Phantasy Star Online. With the team in place, brainstorming soon began on what form Sonic Adventure 2 would take.

Early on, it was decided that one of the main themes of the game would be the dichotomy between good and evil, and to help explore that, the creators came up with new characters that would both assist Dr. Eggman and challenge the established cast of heroes. Though Yuji Uekawa was tasked drawing the final design of the character, it was Takashi Iizuka who conceived Shadow, coming up with the idea to use a dark, anti-hero figure who was similar to Sonic in shape, but not in personality.

When being designed, the character's original name was "Terios," which translates to "reflection of," more than likely to play off of the hero/villain dynamic within the game.

Once Sonic Adventure 2 was announced, the identity and nature of Shadow was a heavily-guarded secret. The character was first shown to the public the first game trailer for Sonic Adventure 2; however, his name was not revealed. GameStop described what little was shown as Anti-Sonic - similar in appearance, but with darker skin, more angled eyes, and a fearsome scowl instead of Sonic's trademark grin." Indeed, the push to build hype for the new character put other characters on the back burner.

When Shadow seemingly died in Sonic Adventure 2, there rose a huge fanbase for Shadow to appear in more games, after being disappointed by his "death". This let Takashi Iizuka input Shadow as a playable character in Sonic Heroes and even star in his own game, Shadow the Hedgehog. In fact, Takashi Iizuka said that they maintained the mystery around the character of Shadow the Hedgehog and had wanted to feature him in his own game since he was introduced. For the Shadow the Hedgehog game, after feeling that it would be inappropriate to give Sonic's character a gun as fans had requested in mailings, Yuji Naka believed that by focusing on Shadow for his own game, they could use his different identity from Sonic to build upon the Sonic brand.

Appearance
Shadow is a black hedgehog with red stripes on his quills, right above his eyes, arms and legs. He has red eyes and white fur on his chest, and his muzzle is tan. He has six quills on his head, four of which point upwards, and two that point down, and he has two spines on his back and a small tail.

Shadow wears white gloves with red and black cuffs with a ring around them. He also wears Hover Shoes, built with jets, and like his gloves, he has red and black cuffs with a ring around them.

Early life
Fifty years before the events of Sonic Adventure 2, a top-secret project known as "Project Shadow" had begun on the Space Colony ARK. Led by Professor Gerald Robotnik, it was a government-sanctioned initiative to create "The Ultimate Lifeform," an immortal being that could be used for the benefit of the nation, likely in a militaristic fashion. While Gerald had initial misgivings to the purpose of the research he was assigned to, he realized that his results might be able to save his granddaughter, Maria. Suffering from the incurable disease Neuro-Immune Deficiency Syndrome, Maria only had a short time left to live, and Gerald was willing to do whatever it took to save her life. Going against his worries of stepping into territory man had no business playing with, the professor immediately began work, hoping that he could apply any newly-gained knowledge to find a cure to N.I.D.S..

Even with the resources at his disposal, Professor Gerald was unable to make significant progress. Without alerting anyone, Gerald decided to plea to the stars for help, contacting the Black Arms race. An alien civilization that lived upon the Black Comet, a celestial object that passed near the planet every fifty years, its leader Black Doom offered to assist Gerald in his quest. He offered his blood - which ended up being the key to perfect the ultimate lifeform - in exchange for the seven Chaos Emeralds, which he would collect the next time he passed through. Knowing that the Black Arms' intentions were less than desirable, Gerald made the deal regardless, albeit with preparations to defeat the Black Arms with the cannon built into the ARK, and was able to successfully create Shadow the Hedgehog.

Once brought to life, Shadow immediately befriended Maria, and they became close during their short time together. Gerald, meanwhile, made precautions for the return of the alien race, ensuring that the Eclipse Cannon - an extremely powerful laser built into the ARK - was compatible with the seven Chaos Emeralds, so that when they did return humanity would be able to defend itself instead of bowing to their whims.

However, Gerald's progress was ruined when it was leaked to G.U.N. how he was able to create the successful prototype. During the meeting between Gerald and the Black Arms, one of the other children aboard the ARK had accidentally seen what transpired, and reported back to those in charge. As ties between the ARK and the United Federation had already been strained, hearing the news of the dealings with an alien race scared those in charge. Afraid of the implications, it was decided to launch an invasion and put a stop to the work being done there.

What happened next was nothing short of madness, as G.U.N. troops descended onto the ARK, causing chaos and confusion wherever they went. Immediately they went after the Biolizard, which they thought was the successful "Project Shadow" prototype, and in the process of putting the creature into stasis lost quite a few soldiers. From there they went about doing damage control, shutting down everything, getting everyone off the ARK, and killing those who resisted if need be. Knowing that the G.U.N. forces would be there at any moment, Maria convinced Shadow to enter an escape pod, her final wish to him that he give the people on the planet a chance to be happy. Wishing him goodbye, Shadow could do nothing as he watched the G.U.N. soldiers storm into the lab, firing a shot which would forever change the hedgehog's life.

Learning of his granddaughter's death, Professor Gerald soon went mad, swearing vengeance on humanity for taking away the only thing that ever meant anything to him. Though just what exactly transpired is cloudy, what is known is that both Gerald and the escape pod that held Shadow were gathered by G.U.N., Shadow being placed in cryogenic storage within Prison Island, and Gerald being incarcerated and charged with the crimes that happened aboard the ARK.

Sonic Adventure 2
Shadow debuted in the game Sonic Adventure 2 as one of three playable "dark" characters, alongside Rouge the Bat (who also debuted in this game), and Dr. Eggman. Dr. Eggman set Shadow free from a G.U.N. base on Prison Island, where he had spent approximately fifty years in suspended animation. In exchange, Shadow agreed to aid the doctor in his plans to take over the world; holding to himself his true intentions as wishing to get revenge for the death of his friend, Maria Robotnik, as he thought she wanted; it is strongly implied that his belief that Maria's final wish was revenge against humanity stemmed from Gerald Robotnik modifying Shadow's memories between Maria's death and Shadow's encapsulation. To achieve this, Shadow revealed the Eclipse Cannon to Dr. Eggman, who later destroyed half of the moon in a demonstration to the populace. Beforehand, he also stole the green Chaos Emeralds from a bank, unknowingly also framing Sonic the Hedgehog for the deed.

He later participated in the second heist alongside Dr. Eggman and Rouge the Bat against Prison Island, where he would plant explosives throughout the island as part of their getaway, although his resemblance to Sonic also resulted in Amy Rose mistaking him for the latter. However, because Tails came to Amy's rescue from Dr. Eggman, he was forced to act fast due to the unexpected delay. In addition, after Rouge ended up getting caught and stranded in the containment area while recovering the four Chaos Emeralds, Shadow, largely because he realized that his plans of avenging Maria Robotnik would be for naught if Rouge perished in the explosion, rushed to get to Rouge and by extension the Chaos Emeralds.

After meeting Sonic for a second time, Shadow also believed that Sonic was trying to copy him. They fought to a stalemate before Shadow was forced to leave to rescue Rouge (with Sonic also learning from Eggman via Shadow's radio that the island was about to blow up), and just barely arrived at Rouge's location and used Chaos Control to warp himself, Rouge, the four Chaos Emeralds and presumably Eggman out at the last possible second. After the demonstration, needing the final Chaos Emerald to fulfill their plans, Shadow pursued Tails' plane at a canyon. Although he was unable to stop them, he nonetheless reported to Eggman that they are headed his way. When Eggman discovered the presence of two apparent emerald readings, and thus deduced Tails' plan of placing a fake Chaos Emerald into the cannon, Shadow departed, apparently to confront Sonic and Tails to stop them for interfering, although Eggman stopped him, wanting to deal with them personally. After Sonic was seemingly killed by Dr. Eggman via a rigged escape capsule, Shadow, witnessing the explosion, guessed that Sonic was only an ordinary hedgehog.

Afterwards, Shadow stumbled upon Rouge's plan to steal the Chaos Emeralds, and deduced that she was in fact a spy for the President of the United Federations, although Rouge then unveiled a report from Gerald Robotnik regarding the Biolizard, claiming, it, not Shadow, was the actual Shadow. However, Shadow was forced to depart after Eggman mentioned an anonymous figure (Sonic) heading towards the Eclipse Cannon, although not before stating that he's still Shadow despite his memories possibly being fake, and that "the fake emerald is good enough for Rouge." He then discovers Sonic the Hedgehog at the area. Shadow, impressed at Sonic's capability of using Chaos Control despite using a fake Chaos Emerald, nonetheless stated that he cannot allow him to live before fighting on a collapsing bridgeway. In the last story, Eggman inserted the final Chaos Emerald, only to initiate a destabilization program on the ARK. Professor Gerald Robotnik then revealed that he had made this function to have revenge for Maria, and that the ARK would destroy the Earth. Sonic, Eggman, Rouge, Tails and Knuckles took a shortcut to the cannon's core so they could stop the Professor's mad plan. Amy Rose then helped Shadow realize Maria's true wish. In a twist of fate, Shadow ultimately aided Sonic when realizing, with Amy's help, Maria's true wish, which was to save humanity. Meanwhile, Sonic the Hedgehog and Knuckles had reached the central core, where they reactivated the Biolizard. Notably, a scene from Gerald Robotnik's diary appeared again. After Shadow defeated the Biolizard, Knuckles used the Master Emerald to stop the Chaos Emeralds. But the Biolizard, being the prototype of Project Shadow, used Chaos Control to fuse with the ARK, continuing its fall. Then, Sonic and Shadow, in their Super States, destroyed the Biolizard. The Ultimate Lifeform prototype became a monster, codenamed Finalhazard. Using their powers, Shadow and Sonic defeated him and executed an enhanced Chaos Control which stopped the fall and warped the ARK. Afterward, Shadow fell to the Earth and was presumed dead.

Sonic Heroes
In Sonic Heroes, Rouge discovers Shadow in a stasis tube located in the deepest part of one of Dr. Eggman's bases, after he was believed to be dead. As she activates the capsule, E-123 Omega begins to attack the newly awakened Shadow, believing him to be a creation of Eggman. Rouge steps in to break them up, quickly ending the skirmish. Shadow discovers that he has amnesia and cannot remember anything before his release, aside from his name and brief images of Maria Robotnik's death. He joins forces with Rouge the Bat and the robot, E-123 Omega, to form Team Dark and find Eggman. In large part because of his amnesia, he also doesn't remember Sonic the Hedgehog when they encountered each other, and thus believed Sonic to be copying him. When confronting the Egg Fleet, Rouge's remark about their being close to the edge of outer space unlocked a part of Shadow's memories. It is later revealed that Eggman had made robotic android versions of Shadow, and the question is raised as to whether or not Shadow himself is one of these androids. Shadow himself also briefly bore witness to a broken Shadow Android earlier, shortly after Team Dark destroyed the Egg Albatross. When rendezvousing with Rouge shortly afterwards, Shadow remarked that some things "never change" when Rouge considered stealing the Master Emerald again due to Knuckles' presence. Ultimately, when Metal Sonic transformed into Metal Overlord, Shadow worked with everyone else to help defeat him. Shadow is last seen with E-123 Omega holding the defeated Metal Sonic.

Sonic Battle
In Sonic Battle, Shadow tries to convince Sonic that Emerl is a threat, but Sonic refuses to believe him, forcing Shadow to fight Sonic, Sonic wins, but Shadow still warns Sonic about the unknown dangers the "Gizoid" represents. Rouge the Bat saves Shadow while they are investigating Dr. Eggman's secret base and takes him back to her home. Shadow talks about how the people of Earth must destroy him and Emerl if they ever want peace, still believing that he is a weapon. It is revealed, however, that he ultimately has the heart and soul of Maria Robotnik, implying he could not be the enemy of humanity. However, Gerald Robotnik's journal entries in this game contradicts truths found in Sonic Adventure 2 and Shadow the Hedgehog.

Shadow the Hedgehog
In Shadow the Hedgehog, while being haunted by the thoughts of his past memories, Shadow witnessed an alien race known as the Black Arms arriving on Earth to invade, where Black Doom appeared before Shadow and told him to bring him the Chaos Emeralds "as promised" before disappearing. Fueled with desire to seek out his past and find the truth behind Black Doom's words in hopes of uncovering his past, Shadow sped off to obtain the emeralds.

After successfully gathering all of the Emeralds, Shadow was confronted by Black Doom, who commanded him to give up the emeralds so that they can begin the 'Ritual Of Prosperity'. Sonic the Hedgehog and the others, including Dr. Eggman, then arrived and told Shadow not to listen to the alien leader. After it was revealed that Black Doom wished to harvest humans as an energy source, he took the Chaos Emeralds from Shadow and used Chaos Control to warp the Black Comet down to the surface of the planet. Black Doom then explained that he helped Professor Gerald create Shadow but only in return for the Chaos Emeralds, which were needed to bring the comet down to the surface, before he paralyzed everyone with a special gas and left them to be devoured by his alien offspring. Due to having the same blood as Black Doom, Shadow was the only one not affected by the gas, and continued forward as he finally put his past behind, swears to never let anyone manipulate him again, and is determined to destroy Black Doom. Black Doom fled, leaving behind Shadow, the only hope for the planet. Shadow caught up with Black Doom and suddenly was attacked by mind control. Black Doom told him that he could control him as they had the same blood running through their veins. Just then, the Chaotix activated a film showing a sane Professor Gerald Robotnik. In the video he told him that he was the only hope for the planet. It was revealed that the only way to defeat the Black Arms was to destroy the Black Comet using the Eclipse Cannon. As the video ended, Maria stepped into the frame and gave Shadow the inspiration he needed to break through Black Doom's control. Black Doom escaped and prompted Shadow to use the Chaos Emeralds to become Super Shadow and fight the alien leader. Black Doom, now in his Devil Doom form, fought Shadow but was defeated. Shadow then used a super-powered Chaos Control to warp the Black Comet back into the planet's orbit and tear it apart with a blast from the Eclipse Cannon. On board the ARK and with the world now safe, Shadow looked at a picture of Maria and Gerald before tossing it away, resolving to put his past behind him and choose to move forward.

Sonic the Hedgehog (2006)
In the 2006 game Sonic the Hedgehog, Shadow is a playable character and has his own storyline. Shadow has a new enemy called Mephiles the Dark. In this game, his will intertwines with those of Sonic and a new character, Silver the Hedgehog. In this role, Shadow, now a GUN agent, is dispatched to Dr. Eggman's base at White Acropolis to rescue their agent (Rouge), who was last contacted 26 hours prior. After storming the base and taking out the robots in the outer perimeter, he started the mission upon being briefed. However, by the time he arrived at the main gate, he encountered Rouge who at the same time opened the gate, to which he explained to a surprised Rouge that he had orders directly from the President to rescue her. Afterwards, Shadow was asked by Rouge whether he wanted to know what she was sent to retrieve. Shadow did not care, as he was only sent to rescue her. On the way to the extraction point, then were ambushed by several Eggman Robots, including the Egg Cerberus.

Upon arrival, he learned the history of Kingdom Valley, including the Solaris Project .He and Rouge encountered the new villain, Mephiles the Dark when the Scepter of Darkness falls and shatters (as Shadow rescued Rouge from freefall when she and the scepter were knocked away by Eggman). Mephiles was sealed inside the Scepter of Darkness and was subsequently released with the relic's destruction, adopting Shadow's appearance due to absorbing his shadow. Shadow and Rouge is sent to the future as part of Mephiles' "one way ticket to oblivion," and shortly after their discovery, encountered Sonic, Tails and Knuckles, who had themselves been transported to the future. Shadow then told Sonic that the only way to return to the present is to find two Chaos Emeralds and then perform Chaos Control on each other. Shadow and Rouge then found a Green Chaos emerald, but then discovered Omega's husk. Shadow then discovers that Omega's on standby mode. As they are unable to do a thing for him, Shadow and Rouge reluctantly leave Omega behind. They then rendezvous with Sonic's group. Upon discovering that another Chaos Emerald was near the volcano, Shadow and Sonic proposed to locate it. Upon finding the Chaos Emerald, they then fought Iblis, a fiery monster within the volcano. After dispatching of the monster, Shadow then proceeded to use Chaos Control with Sonic, opening a time hole to their present. Before Shadow could rejoin Rouge and the others, he noticed Mephiles' presence nearby and pursued him. He then found Mephiles on a volcanic platform and questioned the demon whether he was responsible for the world's destruction. Mephiles then revealed that in the aftermath of Iblis' destruction of the world, Shadow had been labeled as the enemy of mankind, due to his perceived role in the disaster and due to their fear of his power - he showed Shadow an exact copy of himself, but trapped and held in stasis. However, despite the shock of this revelation, Shadow refused to join Mephiles, informing him that he "controlled his own destiny." He then fought Mephiles to a stalemate until Omega intervened (having been earlier dispatched by Rouge to undergo the directive that he and Rouge witnessed earlier), and aided Shadow in defeating Mephiles. They then proceeded to pursue Mephiles, but he escaped from their presence.

He then tried to search for Rouge near the warehouse docks due to her disappearing from GUN's contact. After briefly talking to her, he left determined to find Dr. Eggman and find out who Mephiles was (as Eggman's robots were hunting Mephiles down and mistook Shadow for him). Upon meeting the doctor, Shadow learned a vital clue to Mephiles' possible origins: that it pertained to the accident during the Solaris Project, and was offered more information on the project in exchange for capturing Mephiles. Shadow later interfered with Silver's ambush of Sonic and fought him. Due largely to his use of Chaos Control, he managed to overpower Silver. However, when Silver's use of Chaos Control interfered with his, he informed Silver (who had been trying to kill Sonic to prevent his bad future from occurring due to Mephiles' suggestions) that Mephiles had in fact been trying to eliminate the past, and beckoned that he accompany him to the past if they are to discover the truth of what happened ten years prior. Shadow then entered the area just as the accident occurred, and checked on the Duke's body, although he soon witnessed the birth of both Iblis and Solaris. Shadow then pursued Mephiles, although not before being handed by the Scepter of Darkness by the Duke to seal Mephiles, while Silver went after Iblis, rendezvousing briefly to get by a switch in their paths. Shadow then proceeded to use Chaos Control when cornering Mephiles, and then sealed him in the scepter, although not before the latter threatened that he will die in the future. He then returned to the future, informing Silver that he's leaving the scepter behind because he already knows its fate.

He then requested that Rouge contact GUN to see what the scepter was made out of, hoping to recreate it. However, as GUN was unable to find anything in the database regarding the scepter, they instead had to find someone with archaeological knowledge on the object. They then rescued an archaeologist, who informed them that it would appear at a priests fountain by lighting black flames, which Shadow accomplished via his Chaos powers. He then rendezvoused with Omega upon learning that the latter had cornered Mephiles. By the time he and Rouge arrived, however, Shadow discovered that Omega had furiously driven Mephiles off. Omega then admitted that Shadow, in the future, is sealed away by the reprogrammed Omega, and explained to Rouge why he did so. Shadow then returned to Soleanna, also taking out several of Iblis's and Mephiles' henchmen that had invaded the city from the desert. In gratitude, Lord Regis, acting under temporary authority after Eggman had kidnapped Elise a third time, opened the way to the desert. Deducing that Mephiles needed at least one Chaos Emerald to reform with Iblis into Solaris and devour time, Shadow headed to some ruins that Mephiles was headed to, most likely because a Chaos Emerald was nearby. However, he found Mephiles getting the Emerald in the ruins' inner sanctum. When asked once more to join Mephiles, Shadow exposed what Mephiles' true plans were, to which they then fought in an intense battle.

Although Shadow, Rouge and Omega ultimately won, Shadow's attempt to seal him failed due to Mephiles time traveling to his encapsulation and absorbing Shadow's power via his shadow, alongside his gaining of a Chaos Emerald. Undeterred, Shadow, upon declaring to the newly created Mephiles clones that he will fight as he always had even if the world declares him to be his enemy, and proceeded, alongside his allies, to plow through the Mephiles clones with his full power backing him. Ultimately it was for naught, as Mephiles nonetheless gained hold of the seven Chaos Emeralds (an event Shadow briefly witnessed immediately after slaughtering the clones when the yellow and green Chaos Emeralds glowed intensely) and merges with Iblis, becoming Solaris. Shadow also discovered that Mephiles had killed Sonic to ensure Iblis' release (due to her sealing of Iblis inside of her weakening due to crying), and then proceeded to find the Chaos Emeralds to revive Sonic. Afterwards, with Super Sonic's help, he turns into Super Shadow and joins him along with Super Silver to defeat Solaris. The events of the game are then erased and do not occur, possibly leaving his future open.

Sonic Rivals
Shadow appears in Sonic Rivals as a playable character, alongside Sonic, Knuckles, Silver and Metal Sonic. Summoned to a strange island by Dr. Eggman via a cryptic transmission asking for his aid, Shadow is able to successfully locate Eggman, but once he mentions the cryptic message to the doctor, Eggman denies it. The mystery continues to unfold itself as Rouge warns him of an impending danger and upon stumbling across a secret about Eggman, her transmission is cut short. Shadow continues his quest to uncover the truth about Dr. Eggman.

Upon encountering him several times, Eggman admits that he is Doctor Eggman Nega who plans to take a picture of the entire world (and trapping it in a card) within his camera. The real Doctor Eggman is eventually rescued who escorts him to Nega's space station to stop Nega's ultimatum. Along the way, he is assisted by Silver and Sonic. After defeating Eggman Nega, Rouge is finally rescued. Shadow also appears on four of the 150 collectible cards in the game.

Sonic Rivals 2
Shadow also appears in the sequel to Sonic Rivals, Sonic Rivals 2. He is confronted by Metal Sonic and Eggman via a speaker in Metal Sonic, and tells him that he needs help. Before he can ask questions, he and Metal Sonic find Espio and Silver. Curious as to why Silver has returned to the present, Shadow begins to follow Silver while Metal Sonic follows Espio. Eventually, Shadow forgets to ask the Doctor why he is helping him and just continues to work with Metal Sonic. Shadow discovers that Eggman Nega is trying to release the Ifrit with the seven Chaos Emeralds. He enters the Chaotic Inferno Zone to press a switch inside the dimension to seal the Ifrit in its own dimension and after engaging it in a battle, he and Metal Sonic proved to be victorious but they are trapped in the process. Metal Sonic tears himself open to reveal a Chaos Emerald, and Shadow uses Chaos Control to warp them back to their own dimension.

Sonic Chronicles: The Dark Brotherhood
Shadow appears in Sonic Chronicles: The Dark Brotherhood where he first searched for Omega who disappeared looking for Eggman's robots. The first fight against Shadow takes place in Mystic Ruins, though, depending on the player's choice of dialogue, Sonic may not have to fight him. If, however, the player chooses the more hostile dialogue options, Sonic will have to fight Shadow. The second encounter happens when the team reaches Blue Ridge Zone. At the start of the battle, Shadow states that while he can't outrun Sonic, he can outfight him. After suffering damage at the hands of Sonic and his team, Shadow flees from the scene. Sonic is the only one fast enough to catch him, so once Sonic catches up, the two have a showdown without the rest of the group. When Sonic ultimately wins, Shadow remarks that Sonic "has been practicing."

At first, Shadow only joins Sonic's team to help find Omega, but when he finds out that Omega was attacked by the Nocturnus, he remains with the party to help defeat them. If Shadow happens to be included in Sonic's team when they are about to face Commander Raxos, Shadow states that he can see many ways out this situation for himself but not for the others, possibly meaning he could simply use Chaos Control to escape leaving the others to their fate. In combat, Shadow deals medium attack power and has medium armor and is as quick as Sonic, allowing him three attacks per round.

When Omega joins the team, they can work together to use "Focus Field." When Rouge the Bat is in the party, the three can use "Metal Storm," which sends Omega through the air like a missile at the enemy. Shadow can team up with Sonic to use a move called "Atomic Strike," in which the two hedgehogs use spin-dashes to circle around all of the enemies to create an electrical field.

Sonic Free Riders
In Sonic Free Riders Shadow entered the World Grand Prix with Rouge the Bat as "Team Dark". The duo however, was only interested in the large cash prize and treasure that was given to the winners.

When the World Grand Prix started, Shadow and Rouge were fifteen minutes late to the opening ceremony. When they arrived, Omochao complained about their tardiness, but Shadow remarked that he had no interest in formalities. Discontent with the rule that three members were required for a team, but accepting it nonetheless, Team Dark chose their third teammate, a E-10000B, on a whim. At the races, Team Dark was insulted by their first opponent, Team Babylon. However, Shadow mocked his opponents in return as his team kept beating them.

After defeating Team Babylon, Shadow and his team faced Team Heroes. Though Sonic praised Shadow's earlier performance, Shadow replied that his opponents were no challenge for him. During their face-offs, E-10000B began to overheat, but Shadow showed the robot no sympathy. Insisting to continue the competition anyway, Shadow faced off against Sonic in a final race and won. Having beaten Team Heroes, Shadow told Sonic that he would never beat him.

In the finals, Team Dark faced Team Rose and was just one race away from winning when E-10000B began to smoke. However, Shadow kept pressuring the robot to continue. The two teams then quickly began arguing over how Shadow and his team treated their teammate. In the end, E-10000B was moved to the repairing department, while Shadow and Rouge had a final race with Team Rose by themselves. After beating Team Rose, Shadow and Rouge went for the Grand Prix Headquarters unannounced and took the cash prize and treasure themselves. As they were leaving though, Omochao informed them that they had only taken the dummy drops for the display and that the real prize was locked away, meaning they had to attend the award ceremony to get it.

Near the end of the World Grand Prix, Team Dark and the other teams came down with an equal amount of victories, and Shadow came to the award ceremony with the others to collect their prize. Once there, they were all told by Dr. Eggman (under his alias King Doc) that they had one more race against his Gear-jockey robots. Shadow quickly saw through Eggman's ruse, but the doctor had them race anyway. After the race, however, Eggman revealed himself and announced that that he had been collecting all the data on the racers in the Grand Prix with his E-10000 to make the ultimate Extreme Gear that he could use for his own agenda and challenged them all to a race. After beating Eggman though, Shadow noticed that E-10000B was spewing out a lot of smoke. Metal Sonic then revealed himself as the one controlling E-10000B and passing fake data to Eggman, explaining for the doctor's loss.

Shadow and the others then watched as Metal Sonic challenged Sonic the Hedgehog to a race, which the robot lost. Afterwards, it was revealed that Eggman never had any prize to give to the winners of the World Grand Prix. However, Shadow remarked that it was nothing new to him, just like the doctor's schemes.

Sonic Colors (DS)
Shadow In the Nintendo DS version of Sonic Colors, Shadow was hanging on Asteroid Coaster seeking information when he found Sonic and Tails, and gave Sonic a mission to test out if Sonic was still capable of fighting Dr. Eggman. After the mission, Shadow declined any hint of concern for the duo, but Sonic took it as a compliment.

Reuniting with E-123 Omega, Shadow and his friend discovered secret amusement ride of Eggman's. On their way to investigate, they were joined by Sonic and Tails. They arrived at a lab where Tails discovered records of an experiment called Project "Mother" on the computers. Shadow was disappointed they did not find more to help, but Sonic just was just happy to find something and left. Omega then asked why Shadow gave Sonic information, to which Shadow said he was just happy to let Sonic do all the racing around. Omega found this hard to understand since Shadow and Sonic were equals, but Shadow just replied that data would not tell him everything, leaving the automaton stumped.

Sonic Generations
Shadow appears as a rival boss in the game Sonic Generations. Like all the other characters in the game, Shadow is sucked into the White Space by the Time Eater. After completing all acts in the Dreamcast era, Shadow can be found in the City Escape hub. When found, he is waiting for Sonic, stating that he neither knows nor cares where they are, as long as he gets a chance to finish Sonic. He has a unique rival battle, where the two have to race each other on a looped pathway to and gain Power Cores to unleash special attacks. The battle is won when one depletes the other's ring count whilst using a special attack.

Shadow appears later on in the Center of Time, motivating both Sonics, alongside Rouge and the all the other characters after their initial defeat. After the Time Eater is defeated, Shadow shows up at Sonic's birthday party along with all the other characters. He is the only character who does not wave goodbye to Classics Sonic and Tails in the end.

Sonic Riders
Shadow is an unlockable character in the game Sonic Riders after beating the Hero Story Mode. He is a Speed type character, with his default Extreme Gear, Darkness, which he uses to skate like his default shoes. His Level 1 Attack is "Energy Ball," which temporarily stuns a nearby opponent; the Level 2 attack is "Back Kick," which makes an opponent temporarily lose his or her balance, and the Level 3 attack is "Chaos Control," which freezes a nearby opponent so that Shadow can easily pass them. He plays no role in the story, though.

Sonic Riders: Zero Gravity
He appears in the sequel Sonic Riders: Zero Gravity as a speed character and his default Gear is called the Black Shot. Again, he is unlocked by completing the Hero Story. Once again, he plays no role in the story.

Sonic and the Secret Rings
Shadow appears in Sonic and the Secret Rings, being the first unlockable character for the Party Mode by obtaining thirty Fire Souls. However, he has no role in the game's story.

Sonic and the Black Knight
Shadow appears in Sonic and the Black Knight as Sir Lancelot. He is the most loyal to the King at first and said to be the most skilled of the Knights of the Round Table. After Sonic faces him in a duel and wins (Lancelot is the first Knight to be fought and the second Boss in the game), his sword is taken. Despite being Shadow's parallel, Lancelot still shows the ability to use Chaos Control with his swordplay. This is most prominent in the optional rematch with Lancelot, where he uses Chaos Blast, Chaos Control, and Chaos Spear. When in combat against Lancelot's stronger potential, the player must not only land many hits, but time them closely or risk fierce damage. In addition, Lancelot can use a move called Chaos Punishment, where he uses a series of Chaos Controls and slashes at every enemy nearby.

Mario & Sonic at the Olympic Games
Shadow also appears in Mario & Sonic at the Olympic Games as a speed character along with Sonic, Yoshi, Princess Daisy, and Metal Sonic (who was not in the first of the series).

Like all other characters, Shadow has five missions and one bonus:
 * Don't let Sonic pass you in 100m
 * Throw 3 times that the total of them is at least 220m in Javelin throw
 * Collect all stamina in Cycling
 * Use special attack as a final move in dream fencing
 * Use items to all your opponents in Dream race
 * Defeat Luigi in dream shooting

Mario & Sonic at the Olympic Winter Games
He also appears in the game's sequel, Mario & Sonic at the Olympic Winter Games. Shadow helps Mario and Sonic make a deal with Rouge and open a gate in Sparkleton with Chaos Spear after they beat him in a Dream Ski Cross Racing match during the DS Adventure Tour. He later goes on to help defeat Bowser and Dr. Eggman.

Mario & Sonic at the London 2012 Olympic Games
Shadow makes a return in Mario & Sonic at the London 2012 Olympic Games. He is a Speed type character in the game.

Mario & Sonic at the Sochi 2014 Olympic Winter Games
Shadow reappears in Mario & Sonic at the Sochi 2014 Olympic Winter Games. He is once again a Speed type character.

Mario & Sonic at the Rio 2016 Olympic Games
Shadow appears in Mario & Sonic at the Rio 2016 Olympic Games. He is a Speed type character.

Super Smash Bros. series
Shadow is an Assist Trophy in Super Smash Bros Brawl, found after Sonic becomes a playable character. Shadow activates Chaos Control when he is used, slowing down the user's opponents.

Shadow reappears in Super Smash Bros. for Nintendo 3DS and Wii U with the same role he had in Super Smash Bros. Brawl.

Sega Superstars Tennis
Shadow is also an unlockable playable character in Sega Superstars Tennis.

Sonic & Sega All-Stars Racing
Shadow appears in Sonic & Sega All-Stars Racing sub-series of the Sega Superstars games along with notable Sega all-stars. In the game, Shadow drives the Dark Rider, a modified G.U.N. motorcycle with the Black Arms insignia on the fuel tank. His All-Star Move turns him into Super Shadow and has him flying through the track while launching exploding Chaos Spears at everyone that gets into his line of fire.

Sonic & All-Stars Racing Transformed
Shadow, like other all-stars such as Sonic or Amigo appear in the game's sequel, Sonic & All-Stars Racing Transformed, but instead of his motorbike, he drives an experimental G.U.N vehicle that has tank treads instead of wheels. In order to test his vehicle's raw power, Shadow entered the race. For transformations, the vehicle transforms into an armored military speedboat for water and a jet for flight. He is unlocked with 35 stars in the World Tour. He also has 2 stickers in the game, one can be unlocked by winning a race with him, and the other can be unlocked sending a certain amount of challenges.

Sonic Dash
In late July 2013, Sega released a global challenge in Sonic Dash: have Sonic run 100 laps around the world to unlock Shadow by August 5. Along the way were some side rewards. The challenge was completed on 2 August.
 * 25% 10 Revive Tokens
 * 50% 10 Super Headstart
 * 75% 10 Red Rings
 * 100% Shadow!

Sonic Runners
In Sonic Runners, Shadow is a playable Speed Type character. In gameplay, he can perform a triple jump and boosts the Score Bonus by 75%.

During the "Birthday on Windy Hill" event, Shadow saved Team Sonic's life when Dr. Eggman lured them into a trap. Gruff as ever, Shadow destroyed Eggman's Death Egg drone with his Chaos Blast and sent the doctor off. However, Shadow rejected Team Sonic's offer to join them in their confrontation with Eggman. While having no interest in going to Sonic's subsequent birthday party, he told Rouge to give Sonic his regards.

Personality
Shadow is a brooding loner, to put it bluntly. He is rarely seen with others for an extended period of time, and distances himself from essentially everyone. He is usually soft-spoken, silent and only says what he needs to before a fight. However, Shadow never bluffs. If he makes a threat, he has every intention of carrying it out.

Shadow constantly refers to himself as the Ultimate Lifeform and like Sonic can be extremely arrogant, often belittling his opponents and insulting their lack of strength. Shadow also has a ruthless and merciless edge in combat that all other characters in the series lack, and displays a natural "killer instinct".

Shadow's infamous ruthlessness and aggression leads to fear and a nervousness that inhibits characters from his unshakable intent or sheer power in combat. Numerous characters from the Sonic series have shown absolute dread from encountering Shadow. Shadow's enemies never treat him lightly; he is one of the very few people Sonic takes seriously and acts hostile towards.

Alongside his dark and violent demeanor, Shadow can be smug and stubborn. He treats others in a very callous manner, throwing in his opinion no matter how cold-hearted it might be, and not caring for whatever the response is.

On occasion, Shadow appears to have some degree of mental instability. This is demonstrated by his instances of post-traumatic flashbacks to Maria's face prior to and during the events of Shadow the Hedgehog, though it could be argued that they were simply an effect of his amnesia''. ''Another example could be that in many games Shadow is featured in, he pursues his foes with disturbing determination; that is to say he'll go to any length to accomplish something he desires or feels should be a certain way, no matter what the cost. In his own game, he also showed a rather coarse language.

Shadow also possesses some sense of identity, as evidenced when after falsely being told that he isn't the Ultimate Lifeform due to a lab report. He states to Rouge that even if his memories were fake, he is still Shadow the Hedgehog. Similarly in Sonic Heroes, during the Egg Fleet level, he mentions that even without his memories, he is still the Ultimate Lifeform, Shadow the Hedgehog. These qualities make him rarely susceptible to being manipulated by other forces.

Shadow is not without sentimental emotions and has shown a small sense of compassion from time to time. When Omega begins his attack in Sonic Heroes, Shadow could have easily forgotten about Rouge and engaged Omega without defending her. Instead, Shadow saves her from Omega, despite having absolutely no memory of her. He was also shown to be legitimately shocked when he learned that his goal of gaining the Chaos Emeralds to restore his memories was actually manipulated by Black Doom in order to wipe out humanity. Likewise, when the GUN Commander finally confronts him with his own memories of Shadow's nightmarish creation, Shadow agrees to face judgment if he was indeed responsible for the ARK massacre 50 years ago.

Shadow brushes off most kindness or sympathy that is sent his way. This is shown in Sonic Heroes, when Rouge showed concern for Shadow when he saw a broken android, Shadow curtly brushed her concern away. Also in Shadow the Hedgehog after Sonic suggested some "friendly competition," Shadow turned his back to Sonic and said, "Don't waste my time".

Despite the fact that Shadow often fights for the greater good, he is considered an anti-hero by the most part due to his morality. He does whatever is necessary to get what he wants or feels is right, though this enthusiasm causes him to take risks and jump into situations without fully thinking it through. Regardless, Shadow does have his moments of selflessness, helpfulness and heroism. He nearly gave his life at the end of Sonic Adventure 2 to save Earth and helped Silver uncover the truth of the Solaris Project, after saving Sonic from Silver.

Physical abilities
Shadow is capable of easily matching Sonic's abilities in both speed and power. Although he cannot compare to people like Knuckles the Echidna, Shadow has superhuman strength; with little effort, he can overturn large objects many times his weight and size such as trucks, buses and large slabs of concrete. Like other characters in the series, Shadow can also move at super speeds, an innate talent that members of the hedgehog species possess, and can evenly match even Sonic's speed, who can run at hypersonic speeds. While Shadow's Hover Shoes are credited as the source of his speed, his powerful body lets him easily rival Sonic's world class speed as well. While there is some inconsistency about how fast the two are compared to each other, Shadow has admitted that Sonic is the faster of the two of them.

Shadow is extremely acrobatic, agile and an experienced athlete, capable of gracefully leaping over any obstacles that comes in his way and performing various forms of nimble movements. He has as well radical reaction time to match his movements, being able to react to danger within a split second.

Shadow has incredible resilience to damage, being able to survive otherwise fatal situations even by the standards of superhuman creatures, making him nearly indestructible. He is completely bullet proof and can take a lot of major punishment in battle before he starts to wear down. The most prominent testament to his durability, however was in Sonic Adventure 2 when Shadow survived his fall down to Earth from space and re-entry in the atmosphere before Eggman's robots rescued him, though the experience left him with enough physical trauma to give him amnesia. Even after receiving major damage, Shadow displays a remarkably fast recovery rate, allowing him to quickly get back up in a few moments.

Being the end-product of Project Shadow, Shadow is immortal and does not physically age and presumably immune to disease. Being part Black Arms, Shadow has a connection to the Black Arms' hive-mind, allowing him to sense his kinds' presence and is immune to the Black Arms' nerve gas.

Chaos Powers
Shadow is naturally able to tap into the arcane powers of any nearby Chaos Emeralds to utilize their chaos energy to empower himself and can use a wide variety of Chaos Powers, most of which he does not need a Chaos Emerald to perform. Shadow can specifically harness both positive and negative chaos energy, depending on his state of mind. His Chaos Powers are so intense that if he removes his restraints, he releases tremendous amounts of energy. In this state, Shadow becomes a dynamo of raw power, increasing his abilities so drastically that he can overpower hundreds of perfect Mephiles the Dark clones at once.

Shadow's trademark Chaos Power is Chaos Control, and is possibly the most adapt user of it in the series, having mastered it to perfection. With Chaos Control, he can manipulate space and time to slow down time and warp across space, and can use it delicately enough to distort space in small centralized areas, such as around his fists or in midiar. Additionally, he can mold Chaos Control into a variety of offensive and defensive moves and even use it to heal himself. It is unknown what Shadow's upper limit for warping time and space with Chaos Control is, but it has been shown that he can warp objects and people with him all the way into space.

As described in Shadow the Hedgehog, all of Shadow's Chaos Powers increase in power with the number of Chaos Emeralds he possesses. Furthermore, he can draw power from the Emeralds without making physical contact.

Combat skills
In combat, Shadow is a lethal and extremely powerful force that very few can defeat. He never holds back on his immense strength, making him a brutal fighter with a distinct killer instinct. Shadow's skills are more than a match for even the strongest in the series, and has been able to take down some of the most fearsome foes of the series on his own, such as Black Doom. To best put his skills in perspective, as seen in some of the scenarios in Shadow the Hedgehog, Shadow is the only person so far who has been able to utterly defeat Sonic in combat, even when Sonic had the Diablon for support.

Fighting style
Shadow's fighting style focuses on brutal, unrestrained and powerful hand-to-hand combat. In line with his nature and potent abilities, Shadow has adopted a fighting style where he fights his opponents using powerful blows, such as karate chops, swift punches and roundhouse kicks, to which many of his attacks have a significant amount of force behind them. With the speeds Shadow can move at, he can disable the opponent through the force of his blows alone, while leaving them at the mercy at his incoming attacks.

Shadow's fighting style revolves around making heavy use of his Chaos Powers, especially Chaos Control and Chaos Spear. Using Chaos Control, Shadow can teleport up in front or behind his opponents in battle to launch surprise attacks. Also, Shadow can use Chaos Control to increase the damage he deals to his opponent when striking them, often resulting in significant forces being released and blowing the opponent a certain distance away. To overwhelm his opponents, Shadow will use powerful attacks involving Chaos energy.

Techniques and moves
Like Sonic, Shadow's basic combat moves revolves around the various forms of the Spin Attack where he curls tightly into a concussive ball while in locomotion to damage, mow down, or burrow through obstacles and foes. The Homing Attack allows Shadow to dash in midair toward a target, the Spin Jump lets him curl into a ball and attack opponents by landing on them, and the Spin Dash lets him shoot himself forward as an acceleration roll at full speed while mowing down enemies and obstacles. He is also able perform the Sonic Boost where he turns himself into a highly destructive projectile by moving at high speed, though Shadow uses the fire from his Air Shoes to propel himself forward rather than skating like usual. The Light Speed Dash and Light Speed Attack also allows Shadow to achieve light speed movements for either exploration or combat.

Less frequent techniques that Shadow uses is the Black Tornado, where Shadow jumps into the air, and creates a black whirlwind by circling a particular spot at high speeds which can throw his opponents into the air or blow away armor and weapons. For more direct combat, Shadow has his Chaos Attack where he deal a barrage of chaos energy-fueled strikes to his opponents, and his Spin Kick lets him create a small tornado that can suck enemies to strike them.

Many of Shadow's signature techniques are Chaos Powers. His trademark move is Chaos Control which lets him to manipulate time and space to either warp across space, slow down time and distort space to form other types of Chaos Powers. His second most used Chaos Power is his Chaos Spear technique, where he throws bolts of chaos energy at his opponent. His most powerful technique, however, is the Chaos Blast. With this, Shadow releases a shockwave of chaos energy that eliminates everything within its range. Alternatively, he can focus it into a beam for more concentrated damage.

Another special Chaos Power Shadow uses is his Chaos Boost technique where Shadow covers himself in chaos energy. While in his Chaos Boost state, Shadow gains more destructive power, is able to move at warp speed, and is nearly invulnerable. It also enables Shadow to access more advanced and powerful Chaos Powers as well.

Miscellaneous skills
As seen in Sonic Free Riders, Shadow has proven himself to be an expert Extreme Gear rider, as seen in the tournament where he was able to put up quite a fight and even defeat some of the world's best Extreme Gear riders. When riding on an Extreme Gear, Shadow is skillful enough to ride on rails, execute complex tricks while in midair, and even perform his Chaos Powers and combat moves with ease. Also, Shadow may have some knowledge about machinery, being to fiddle with a deactivated Omega and deduce he was in stand-by mode.

Not being the one above using weaponry and equipment, Shadow has demonstrated proficient skills in a wide range of firearms, semi-automatics, heavy assault, and close-combat weapons, and as well and all forms of vehicles, militaristic or otherwise.

Equipment
Shadow wears a pair of specialized called Hover Shoes. These footwear are the primary source of Shadow's speed, producing small jet streams that lets him hover-skate at speeds rivaling Sonic's; with their help, Shadow is supposedly even able to move at speeds surpassing Sonic's, making him one of the fastest characters in the series. Alternatively, Shadow can use his Hover Shoes to produce fire to attack opponents with or achieve midair flight, though the latter is limited to hovering.

Shadow wears two Inhibitor Rings on his wrists that limit the amount of power he uses during combat and other situations. By removing them, Shadow is able to use his full power, turning him into a nigh-unstoppable force.

Super Shadow
By harnessing the power of the seven Chaos Emeralds, Shadow can enter a Super State, transforming him into Super Shadow. In this state, all of Shadow's abilities far surpasses his normal ones and his Chaos Powers are increased to their full limit. He is as well able to fly and is nearly invulnerable. Initially, Shadow found it difficult to stay in this state due to inexperience, but he has since mastered it.

Hero Shadow
In Shadow the Hedgehog, Shadow is able to transform into Hero Shadow with the use of positive chaos energy, whenever his mind is fueled by thoughts of justice. In this state, Shadow is temporarily invincible and can perform a large scale use of Chaos Control. However, it only lasts for a short time.

Dark Shadow
In Shadow the Hedgehog, Shadow is able to transform into Dark Shadow with the use of negative chaos energy, whenever his mind is fueled by thoughts of evil. In this state, Shadow is temporarily invincible and can perform a large scale use of Chaos Blast. However, it only lasts for a short time.

Color Powers
By harnessing different variants of Hyper-go-on from Wisps, Shadow can use specific Color Powers to transform into a certain form, such as a drill, a laser or even a planet, each one possessing its own unique abilities. So far, Shadow has been able to transform into the Cyan Laser, Yellow Drill and Indigo Asteroid. However, these transformations require a steady supply of Hyper-go-on to be maintained.

Weaknesses
While not having any physical weakness, Shadow was initially a somewhat easy target for manipulation during the time he had amnesia due to his confusion about who he was. Dr. Eggman could fool him with his lies about his past, and Black Doom could subtlety manipulate him using visions of his own dark past. However, after learning of his true purpose, Shadow is now not as easily deceived as he was before.

Being part Black Arms, Shadow is partially an extension of Black Doom, making him vulnerable to mind control exerted by Black Doom himself. However, Shadow can fight this influence through sheer resolve and willpower.

Gerald Robotnik
Shadow was created by the renowned scientist Gerald Robotnik, using Black Doom's DNA. Gerald had made many attempts to create the Ultimate Lifeform before Black Doom and his children, the Black Arms, came to Earth. Unfortunately, the closest he came was the Biolizard. Black Doom, however, approached Gerald and offered his help, but only on one condition; if Black Doom helped Gerald, the professor must promise to deliver the seven Chaos Emeralds to him. Gerald agreed to these terms, and Black Doom gave some of his DNA, which was added to the samples that Gerald had already obtained. The result of this experiment was Shadow the Hedgehog. Gerald seems to be one of few people whom Shadow felt happy around, and the professor might have acted as a surrogate father to him. This is further proved when Gerald refers to the hedgehog as his "son." Despite this, however, when defeating the Finalhazard, Shadow states that he promises to "destroy all evil that the professor had created," implying that while he might still respect Gerald Robotnik, he nonetheless feels that any bad things that Gerald Robotnik had done after going insane must be stopped.

Doctor Eggman
Shadow's approach to Eggman is different from most characters in the Sonic series. Shadow sees Eggman as the super-genius he has proven to be, rather than the megalomaniac that Sonic and the others see him as. This can be backed up by the fact that Shadow almost always calls Eggman by his title "the Doctor", as opposed to his alias of "Eggman." Eggman has shown similar respect by referring to Shadow's powers as "spectacular", and by how he sometimes applauds Shadow. This is seen in Shadow the Hedgehog during a cutscene where Eggman remarks, "Excellent job, Shadow."

Even though Shadow and Eggman display a level of respect toward each other, they also show a dislike toward one another. This can be backed up in Sonic the Hedgehog when Eggman refers to Rouge as his "dear Rouge", and just flatly states Shadow's name. In the same game, when Shadow breaks through the ceiling of his base, Eggman responds with, "wouldn't the door have been easier? So....What do you want now?" The disgusted tone may refer to Shadow having just smashed the ceiling. In Shadow the Hedgehog, Eggman tells Shadow, "You will obey me, or there will be dire consequences". In three possible storylines in Shadow the Hedgehog, Shadow even kills Eggman. Even though Shadow and Eggman have some respect for each other, they still do not regard each other as anything more than an acquaintance.

Black Doom
The relationship between Shadow and Black Doom may have been brief, but has played a significant role in Shadow's life. Shadow was made from Black Doom's blood, in a deal between the alien and Professor Gerald; this technically makes Black Doom Shadow's biological father. Black Doom, at first, tried to get Shadow on his side by playing on what remained of Shadow's painful memories of losing Maria. Regardless of the path taken during gameplay, Shadow defeats Black Doom and destroys the Black Comet along with the Black Arms.

Throughout the events of Shadow the Hedgehog, Black Doom threatens Shadow and demands extreme loyalty and respect without compassion, even when he aids him. He also doesn't tolerate any kind of mistake or failure, no matter how difficult the task on Shadow's part may be. In the end, Shadow refused to aid him and decided to put the end to his biological father and his "offspring" after learning of his true plans. .

Mephiles the Dark
"You have no desire for revenge. You only crave destruction. Your only lust is to fuel Iblis until there is nothing left of time itself."

- Shadow the Hedgehog, Sonic the Hedgehog (2006)

Mephiles the Dark is one of Shadow's deadliest enemies. When they first met, Shadow did not know him when he expressed a familiarity with him, before Mephiles send him to the future. In Shadow's second meeting with Mephiles, Mephiles tried to convince Shadow to turns him against humanity, but Shadow refused. After the battle, Shadow tried to collect some information about Mephiles to stop him, which led him to investigate Mephiles' origin at the Solaris Project ten years ago. There, Shadow sealed Mephiles in the Scepter of Darkness shortly after his birth, where Mephiles swore that he would remember Shadow and that he would kill him. This made Shadow realized how Mephiles knew him and why he was obsessed with him.

Shadow later faced Mephiles in Dusty Desert where Mephiles tried to convince him to join his cause, but Shadow saw through his deceit and proclaimed he knew that Mephiles only craved destruction. After Shadow failed to seal Mephiles, Mephiles tried to confuse by asking why wanted to save humanity when they would persecute him so why he want save them, but Shadow proclaimed he would always keep fighting. When Solaris later was erased from existence, Mephiles was erased as well, leaving Shadow's relationship with Mephiles unknown.

Maria Robotnik
Professor Gerald's granddaughter, Maria Robotnik, is by far the one person that made Shadow the happiest. She was like a sister to him, and they shared the same dream; to visit Earth. Unfortunately, G.U.N. deemed Project Shadow to be too big a threat to the world. As a result, they eliminated everything they could in relation to the project, including the people. Maria was shot and killed by G.U.N. during the raid on the ARK. Her last parting words were "Sayonara, Shadow the Hedgehog," Shadow still stays strong to keep his promise to her and mourned her death, although at the end of Shadow the Hedgehog, he implies that he is putting his past behind him.

Sonic the Hedgehog
Shadow's arch-rival is none other than Sonic the Hedgehog. They became enemies when meeting in Sonic Adventure 2, but later became bitter arch-rivals. Since meeting each other, there has been a never-ending competition between the two, and their battles can range from friendly races to fierce death battles. In any case, one always wants to outdo the other.

When they first met, Shadow believed Sonic to have been copying him, with a mutual belief from Sonic. He later retained this belief in Sonic Heroes, largely because of his amnesia.

Shadow and Sonic frequently fight due to their own views on justice and morality and how to act on them. Their constant disagreements quickly turn into outright death matches. Each does not care what the other thinks of their views. In a sense, the two hedgehogs are polar opposites in every way except their appearance. Almost every time they meet, they fight ferociously. Neither is ever willing to accept defeat. However, their rivalry has developed over time and is now more friendly.

Despite their fierce arch-rivalry, Shadow and Sonic have helped each other on occasions and even acknowledged Sonic's powers as during their adventures. Shadow helped Sonic defeat Metal Sonic in Sonic Heroes, and saved him from Silver in Sonic the Hedgehog (2006). He showed some annoyance because of Sonic's death and admitted that they cannot defeat Solaris without his help. He also motivated Sonic to defeat the Time Eater in Sonic Generations, and even attended his birthday party, despite being the only one not to wave goodbye to Classic Sonic. Overall, while the two still have a mutual strong disliking for each other because of their conflicting views, there is also a mutual respect between them, and they are both perfectly willing to put their differences aside and help each other when needed. Overtime, Shadow has become more confident about Sonic doing what is right, and Sonic has become more acceptant of Shadow's violent attitude as well.

Humanity
Initially, Shadow did not hate humans and promised his best friend Maria to give them a chance to live happy lives. However, his opinion about them changed after G.U.N killed Maria and he came to loathe humanity itself for what they did to her. After his reawakening, Shadow planned to destroy humanity, thinking he had promised Maria revenge at them for her death. However, when he remembered his true promise to Maria, he cast aside his vendetta and risked his life to save humanity.

After losing his memories, Shadow did not care for humans, regarding them as pathetic and held no sympathy towards them. During Shadow the Hedgehog, Black Doom even tried to use Shadow's horrific memories of the tragedies humans had brought him to truly turn him against them. However, when Shadow regained his memories as Black Doom unveiled his plans to make humans food for his kind, Shadow once again chose to save humanity to keep his promise to Maria.

While Shadow still holds a general loathing of humanity, he has made it his mission to protect them due to his promise to Maria, even becoming an agent for G.U.N. In all his encounters with Mephiles in Sonic the Hedgehog (2006), who attempted to make Shadow turn on humans by showing how they would persecute him in the future, Shadow refused to listen and remained steadfast to protect them. During his final battle with Mephiles, Shadow even proclaimed that if the world chose to become his enemy, he will fight like he always have, showing that he will always help humans no matter what.

Knuckles the Echidna
Shadow and Knuckles haven't interacted much, but at times they are either allies or rivals. In Sonic Adventure 2 they didn't have much interaction, but technically they were enemies first and then worked together to save the world from Space Colony ARK. The first real fight between them happened in Sonic Heroes, although Shadow didn't remember Knuckles at the time. After the fight Knuckles jokingly mentioned that maybe they fought Shadow's ghost. In Shadow the Hedgehog Knuckles appears in Glyphic Canyon, Central City and Black Comet stages asking for Shadow's help in Hero missions. In Sonic the Hedgehog he and Shadow loosely worked together again for a time in order to return to the present.

Rouge the Bat
Shadow has a companionship with Rouge the Bat that is based mainly on partnership during the games. The two are teammates in Sonic Adventure 2 and Sonic Heroes, and often work together during mission stages, but they do not spend time in the other's presence outside of duty alliance. This marks them as occasional teammates when it comes down to appreciation, respect, and consideration over the term of "best friends." Shadow has not shared the closeness of opening up to neither Omega or Rouge the way best friends would do, let alone accompanying them as casual company due to his independent and distant nature, unlike how Sonic interacts with his companions. Nonetheless, the fact that Rouge is one of the closest people for Shadow to interact with (excluding Gerald and Maria who are dead) is certain. Shadow was implied to have at least heard of her before their formal meeting onboard the Space Colony ARK, as Shadow responds, "Now I know who you are! You're that government spy, Rouge the Bat, aren't you!" when stumbling upon her true intentions at the controls of the Eclipse Cannon.

In Sonic Adventure 2, Shadow saved her life when Rouge was trapped in Security Hall, though when she questioned him about his actions later aboard the ARK, he told her he only returned for the Chaos Emeralds that she had acquired. However, it's still unknown if he didn't lie; Rouge teased that this wasn't "the whole story." Their conversation was then interrupted by Dr. Eggman.

In Sonic Heroes, Shadow saves Rouge from Omega's fire when not even remembering her. Later, When they find a broken Shadow Android, Rouge looks over to Shadow with pity and asks, "Shadow....?" in a sympathetic mannerism, while he simply dismisses the situation.

In Sonic Battle, Rouge implies that she may hold a certain level of attraction towards Shadow and lets him stay with her at Club Rouge when he is injured during a fight at the Gimme Shelter. Also, while Shadow is dreaming, an image of Rouge appears and he whispers, "Ally." After he regains consciousness, Rouge seems somewhat hurt and offended when he doesn't thank her for helping him.

In Sonic the Hedgehog, Shadow shows he is protective of Rouge's well-being. Once, when catching her from a fall after she was momentarily knocked out by one of Dr. Eggman's robots, and again, when he jumps in front of her after Iblis takes them all by surprise. When E-123 Omega reveals to Shadow that he is the one who traps him in the future; Rouge tells Shadow, "Even if you believe the entire world will be against you, know that I will always remain by your side... Remember that..." Shadow pauses, then strongly replies, "I will." However, this event was erased along with the rest of the events within the game after the "future was reversed."

In Sonic Rivals, after Shadow saves Rouge from Eggman Nega, Rouge tries to coerce him into going treasure hunting with her and suggests the two "take a peek" into their own future using Eggman Nega's device. Shadow declines and the story ends with Rouge still trying to convince Shadow to join her in hunting for the remaining cards.

In Sonic Rivals 2, their encounter was less than friendly from their previous ones to separate the fact their overall relationship seems to be more partner-focused when they ally for the occasion rather than best-friend designated. Shadow is consistently trying to stop Rouge and Knuckles from reaching the Chaos Emeralds at all costs, and seeks to manipulate the Chaos-finding device from Rouge. Rouge asks Shadow on what's going on, saying that Shadow can trust her, and Shadow tells her about the Ifrit. When Rouge mentions her client, Shadow demands to know who her client is, but Rouge refuses against him, leading him to yell after for her to, "get back here." When Shadow catches up to her, Rouge still refuses to tell him about her client as Shadow mildly threatens her, and then she trips him over and replies that he was being "clumsy," and he growls, "Why you...!" The conversation then devolves into a fight between the two.

In Sonic Free Riders, both Shadow and Rouge appear as Team Dark along with E-10000B. Their main focus during the game is winning the treasure and prize money. Unlike in previous games, Shadow seems perfectly content with helping Rouge obtain the treasure she covets.

E-123 Omega
Shadow has a very close relationship with Omega who, other than Maria, may be Shadow's closest friend. This relationship is first shown when Shadow looks out for Omega in Sonic Heroes halfway into the game. This was also shown in Shadow the Hedgehog when Shadow willingly helped Omega in Iron Jungle and Lava Shelter. In Sonic the Hedgehog, both Shadow and Rouge were somewhat saddened by Omega being reprogrammed to hunt down Shadow in the future, due to Shadow being seen as too strong of a lifeform, causing humanity to fear him. The bond between the two may have been strengthened by the fact that Shadow is the Ultimate Lifeform and that Omega is considered the Ultimate Robot and share a common importance to the world.

In Sonic Chronicles: The Dark Brotherhood, Shadow joins Sonic's team to find Omega, he clearly shows anger if the player refuses to rescue him and states that if he doesn't find Omega, then he'll "be very upset". He also states that "he was also my friend" which is the first time Shadow openly calls someone his friend, although he notably only says this after questioning by Sonic, not willingly. This is proof that he doesn't like seeing his closest friends being hurt. This is also shown when the player finds Omega in Metropolis and Shadow orders Eggman to be quiet after saying not to bother checking if Omega's okay. When Tails says that robots are coming, Shadow responds with, "Good. I need to smash something." Again, this is shown when Tails realizes he can fix Omega, Shadow simply orders him to "do it." Shadow and Omega pair up for two POW moves. One is Focus Field, which involves Omega opening fire on a foe with his Gatling guns, then Shadow following up with a Chaos Blast. Team Dark partner up for Metal Storm, in which Shadow sends Omega into the air with Chaos Control. Rouge follows up by kicking Omega, who then collides into the target like a torpedo.

Amy Rose
In Sonic Adventure 2, Shadow and Amy Rose interact twice, but each time seems to gain an odd reaction from Shadow. Amy first meets Shadow when she mistakes him for Sonic and hugs him from behind, while Shadow remains still after having been briefly caught off-guard by her touch. He also does not shake her off or resort to violence. When Amy senses the lack of a reaction, she releases him, causing him to glance back at her. Amy demands his name when she realizes that he is not Sonic, but Shadow continues to glare at her quietly. After Amy notices Dr. Eggman, she also realizes the mistake she has made, and runs off screaming. During this, Shadow simply tilts his head when she is out of range as Dr. Eggman tells the team that he'll take care of Amy.

Later in the game aboard the ARK, Amy meets Shadow again and this time does her part in helping by begging Shadow to save the world. At first, Shadow simply replies that it is pointless, but then Amy points out that despite people sometimes being selfish, they were still inwardly good and that saving them was right. Because of this, Shadow suddenly has a flashback of Maria begging Shadow to make people happy. When Shadow comes to his senses he goes off to fight the Biolizard, determinedly and softly telling Amy that he has to keep his promise to "Maria...and [her]."

Amy was also the only one to see Shadow's tear after he remembered that Maria wanted him to save the people that live on Earth, making her the only person to see him cry in Sonic Adventure 2.

During Sonic Battle, Amy shows excitement and concern upon hearing Shadow's survival through Rouge, but quickly becomes angry when Rouge will not tell her why he's there.

During Shadow the Hedgehog, Shadow can choose to assist Amy in helping find Cream the Rabbit and have her fight alongside the player during the stage and in the boss battle, but this time, there is no reward in return. Also, at the end of Shadow the Hedgehog, Amy shows an odd amount of faith and admiration for Shadow, regardless of him being Sonic's arch-rival. When Rouge expresses concern for Shadow following the destruction of the Black Comet, Amy reassures her with her hands clasped and a cheerful smile on her face, "I'm sure he's fine, Rouge! After all, he is Shadow!" which further displays her positive outlook on the black hedgehog and her general optimism.

Commander
The Commander and Shadow were enemies with each other because the Commander blamed Shadow for the death of his family and Maria 50 years ago. Throughout the game, he orders his troops to kill Shadow. After the events of Shadow the Hedgehog, the Commander apologized and invited Shadow over to their organization; this is presumably the time that Shadow became a G.U.N. agent.

Metal Sonic
Shadow, along with Rouge, Omega, and the rest of the teams from Sonic Heroes were distracting Metal Sonic, in his Metal Madness form, so that Team Sonic could transform into their Super state. Sometime later, Shadow and Metal Sonic are forced to work together when Doctor Eggman calls for Shadow's assistance in Sonic Rivals 2. Although they are together for a brief amount of time, Shadow does seem concerned about Metal Sonic multiple times, despite the fact that Metal Sonic is a robot with the inability to speak. Shadow constantly asks him if he's alright and at the end of the game when Metal Sonic tears himself open to retrieve the Chaos Emerald within his body, Shadow tells him to stop, for he fears Metal Sonic will destroy himself. Feeling a possible connection due to his friendship with Omega may be the reasoning for his concern. He also may think that he was doing this on his own intention as he only needs Eggman to speak for him. Another possibility is that since Gerald Robotnik created him, and Eggman, Gerald's grandson, created Metal Sonic, he felt it was right. Shadow does show some deep concern for him as he even talked to Metal Sonic himself instead of Eggman.

Silver the Hedgehog
Shadow and Silver were enemies at first due to Silver being tricked by Mephiles, but became partners later on in Sonic the Hedgehog. They became allies when they worked together after their fight. After using Chaos Control, the two traveled back ten years to witness the Solaris Project accident. The two working together later split up to go after their own targets; Silver watching the King of Soleanna sealing Iblis inside Elise and Shadow sealing Mephiles inside the Scepter of Darkness. After they finished, Shadow and Silver meet up outside the Aquatic Base. They then use Chaos Control to go back to the present. They meet up once again during Solaris' resurrection.

In the Sonic Rivals games, Shadow and Silver are rivals. Shadow does not trust Silver's intentions and speculations about Dr. Eggman's identity, but after he discovered that Silver was right, Shadow showed some tolerance toward Silver. In Sonic Rivals 2, they are at odds; mostly because Silver did not want Shadow getting in his way.

Team Chaotix
Shadow has had several altercations with the detective agency, the first being a confrontation in Sonic Heroes that escalated into a brawl, with their differences then seemingly set aside later when they joined forces against an evolved Metal Sonic. The Chaotix resumed their role as allies in Shadow the Hedgehog, with each member participating as a partner in the hero missions of various levels. Individually, Vector perceives Shadow as a friend, as demonstrated in one of the endings of Shadow the Hedgehog when the crocodile attempted to console him when he concluded himself to being nothing more than a living weapon of mass destruction, though Shadow apparently didn't want to hear it.

Espio has shown his capacity of friendship for the black hedgehog and the two proved to make a good team when they confronted Dr. Eggman. When Eggman tries to lie and manipulate Shadow, Espio tells the hedgehog not to fall for the doctor's tricks and to defeat him first. Charmy has exercised a more enthusiastic relationship with Shadow, demonstrating how much he respects and looks up to him while often stating how "cool" Shadow is. All the Chaotix voices are present in supporting Shadow during the last story as well as Expert Mode.

Friends/allies

 * Team Dark
 * Rouge the Bat (Best friend)
 * E-123 Omega (Close friend)
 * Team Sonic
 * Sonic the Hedgehog (Ally and rival)
 * Miles "Tails" Prower
 * Knuckles the Echidna
 * Team Rose
 * Amy Rose
 * Cream the Rabbit
 * Big the Cat
 * Chaotix
 * Charmy Bee (Looks up to Shadow)
 * Vector the Crocodile
 * Espio the Chameleon
 * Silver the Hedgehog
 * Maria Robotnik (Best friend, deceased)
 * Dr. Eggman (Depending on Shadow's goal)
 * Metal Sonic (Sonic Rivals 2 Only)
 * Gerald Robotnik (Creator, deceased)
 * G.U.N.

Rivals

 * Sonic the Hedgehog (Arch-rival)
 * Silver the Hedgehog (Sonic Rivals 2)
 * Jet the Hawk

Enemies

 * Dr. Eggman (Sometimes)
 * Metal Sonic (Except Sonic Rivals 2)
 * Biolizard
 * G.U.N. (formerly)
 * Commander (formerly)
 * Black Arms
 * Black Doom (Arch-enemy)
 * Mephiles the Dark
 * Solaris
 * Doctor Eggman Nega

Archie Comics
In the Sonic the Hedgehog comic series and its spin-offs, Shadow is the ultimate life form created by Gerald Robotnik, much like in the games. Prior to the Super Genesis Wave, his backstory was similar to his game counterpart's, having been created by Gerald Robotnik with Black Doom's aid. After the events of the Sonic Adventure 2 adaptation, Shadow was rescued by the Bem aliens to fight the Xorda, and became integral in defending against the Xorda Attack on Mobius. Afterwards, he briefly joined up with the Eggman Empire, but defected to join G.U.N. after learning of his true purpose. His relationship with Sonic the Hedgehog is also less tense in this continuity.

In the new continuity created after Worlds Collide, Shadow and his history is now virtually identical to his game counterpart's.

Sonic X
Shadow also appears in the anime Sonic X, debuting in the "Shadow Saga". Like in the games, his ambition was to fulfill Maria's promise of revenge towards humanity and joined forces with Eggman to seek out the Chaos Emeralds. When everyone but Shadow worked together to save the world from its imminent destruction, Christopher Thorndyke was able to convince him of Maria's true purpose. At the end, Shadow sacrificed himself for the better of the world and was presumed dead.

However, Shadow returned much later in the Metarex Saga under Eggman's side where he was struck by amnesia. Although Shadow rebelled against Sonic and his friends at times, especially when he threatened to kill Cosmo at one point, Shadow remained as an ally for them to defeat the Metarex who intended to destroy the universe.

Sonic Boom
In the Sonic Boom franchise, Shadow is an indirect enemy of Team Sonic and a much darker character in comparison to other characters in the series. He is Sonic's arch-rival, capable of him matching in speed, abilities and looks. His relationship with Sonic is also just as hostile as Shadow's own harsh and anti-social behavior.

Theme songs
The video games have featured several theme songs for the character. Shadow's themes consisted primarily of the techno and industrial genres often with synched vocals that are barely audible in Sonic Adventure 2 and Sonic Heroes, but have shown an increasing preference towards the hard rock genre in more recent games.


 * Sonic Adventure 2: Throw It All Away - Everett Bradley. (A short instrumental version appeared in Sonic and the Black Knight in the event called "Sir Lancelot Appears.") Also, the song Live and Learn seems to also be his theme, but shared with Sonic, since it is the final boss theme when Super Sonic and Super Shadow are used. An instrumental also played in the game, Shadow the Hedgehog when Shadow was turning into Super Shadow in the final story. A short version of this song also appears when standing in front of Shadow in the Sonic Generations hub world.
 * Sonic Heroes: This Machine - Julien-K. (This was a team theme shared with Rouge and Omega.)
 * Shadow the Hedgehog featured multiple themes:
 * I Am... All of Me - Crush 40
 * Almost Dead - Powerman 5000
 * Waking Up - Julien-K
 * Chosen One - A2
 * All Hail Shadow - Magna-Fi
 * Never Turn Back - Crush 40
 * Sonic the Hedgehog (2006): All Hail Shadow (Remix) - Crush 40 (This appears in Sonic and the Black Knight when the Medal of Lancelot is equipped)
 * In addition, there are several vocal level themes associated with Shadow's character in Sonic Adventure 2:
 * White Jungle: Rhythm and Balance - Everett Bradley
 * Final Chase: The Supernatural - Everett Bradley
 * Biolizard: Supporting Me - Everett Bradley
 * Radical Highway: Vengeance Is Mine - Jun Senoue; in Shadow the Hedgehog a remix is used in 2-Player Mode.
 * Also, a special remix of Tripod Baby performed by M-Flo was released as a promotional song for Shadow.

Reception
Shadow was ranked as the second favorite Sonic character, beaten only by Sonic the Hedgehog himself, in the official Sonic character poll. However, many game reviewers, such as GameSpot, have called Shadow a "clone" of Sonic. Game Revolution described his character as a "quintessential anti-Sonic." In a 1UP.com feature about "How Sega Can Save Sonic the Hedgehog," Jeremy Parish wrote that of the "tagalongs" that the series must ditch, Shadow's character was the most in need of it.

Trivia

 * Though the design of Shadow was meant to be a secret until such time Sega decided to reveal the finalized version, details of the character were leaked when ReSaurus announced they were making figures of Shadow and Rouge, much as they had for the first Sonic Adventure title. Ironically, the company went out of business before they could release these figures to the masses.
 * According to Takashi Iizuka, Shadow is like everyone else in the series in that he requires at least one Chaos Emerald in order to use Chaos Control; however, Shadow has appeared to use Chaos Control or its related powers during gameplay of some games without visible Emeralds nearby, most notably in Sonic Battle when he relinquishes his Emerald but retained his abilities. According to Shadow, this is due to him keeping Maria in his heart.
 * Shadow and Knuckles were originally confirmed to appear in Sonic Unleashed. Although Shadow doesn't appear, he is briefly mentioned; during an interview with Brenda, she will ask the name of the creature that came from the planets core. Sonic can incorrectly answer 'Shadow the Hedgehog.'
 * It should be noted that the light of Shadow's Hover Shoes has differed in games, as in Sonic Adventure 2 and Sonic Heroes it was white, but in Shadow the Hedgehog onwards their light is yellow, occasionally with an orange hue and in Sonic the Hedgehog (2006) it was red.
 * In the Japanese commercial for Shadow the Hedgehog, Shadow is seen dancing.
 * In his artwork for Mario & Sonic at the Olympic Games, Shadow is missing his tail.
 * Shadow uses his left hand when using weapons in Shadow the Hedgehog. His counterpart, Lancelot, however, fights with his right hand, possibly because of the Wii motion control. In Sonic the Hedgehog Shadow always leads with his right for his attacks during cutscenes. Shadow may either be ambidextrous or have left eye dominance, seeing as those with left eye dominance are recommended to fire guns whilst favoring their left hand. He also tends to cross his right arm under his left arm in most artworks.
 * The Official Game Guide for Sonic Generations mentioned that a scientist is the one who ejected Shadow's capsule to the earth, however, he was ejected by Maria Robotnik.
 * In the 2011 Guinness World Records Gamer's Edition, Shadow placed 25th in the "Top 50 Video Game Characters of All Time" while Sonic placed tenth.
 * In Sonic Heroes, Shadow is shown to be faster than Sonic in grinding, but this has been modified in Sonic the Hedgehog.
 * Shadow's trophy pose in Super Smash Bros. Brawl is almost identical to his artwork for Sonic the Hedgehog (2006).
 * Shadow's skin color is tanner in his 2D artwork than his 3D artwork.
 * Normally Shadow is seen with red eyes, but in his Sonic Chronicles artwork and pictures his eyes are more of an orange color, but this may be because the artwork in Sonic Chronicles: The Dark Brotherhood was made by someone other than the usual Sonic Team artist.
 * In the game Sonic Chronicles: The Dark Brotherhood, Shadow is missing a quill on his head. This is also present in Sonic X.
 * In Sonic Generations, the player may be rewarded with the fourth Chaos Emerald for defeating Shadow (third if he is fought before Perfect Chaos). Coincidentally, in his own game, Shadow mentions the fourth Chaos Emerald in a line, "Where's that damn fourth Chaos Emerald!?", which has since gained Internet popularity.
 * Shadow's three main Chaos abilities are generally color-coded in relation to the three Chao alignments. Chaos Control requires positive chaos energy that generally glows blue, as Hero Chao have blue markings. Chaos Spear is generally depicted as being yellow-white, while Neutral Chao have yellow markings. Chaos Blast requires negative chaos energy, and is generally red, whereas Dark Chao have red markings.
 * In Sonic & Sega All-Stars Racing, Shadow's profile says he likes "nothing."
 * In the 2D indie fighting game Skullgirls Encore, the 17th selectable color palette of the character Fukua is a direct reference to Shadow the Hedgehog.
 * Shadow's trophy pose in Super Smash Bros. for Nintendo 3DS / Wii U resembles his artwork for Sonic Rivals.
 * Strangely, in the leaked transcript of Sonic the Hedgehog (2006), Shadow was described as a "fifteen-year-old" hedgehog, just like Sonic, unlike all the other official materials which do not put an actual age to him.
 * Despite many fans having speculated that Silver is related to Shadow due to Sir Lancelot and Sir Galahad's relationship in Arthurian lore (where the latter is the son of the former), Takashi Iizuka has confirmed that Silver is not a descendant of Shadow.
 * Shadow is the only major character in the series who has a known backstory.