- For other uses of the term, see Shadow the Hedgehog (disambiguation).
Shadow the Hedgehog (シャドウ・ザ・ヘッジホッグ Shadō za Hejjihoggu?) is a fictional character from the Sonic the Hedgehog series. He is an anthropomorphic hedgehog/Black Arms hybrid and the arch-rival of Sonic the Hedgehog. Shadow was created as the "Ultimate Life Form" (究極生命体 Kyūkyoku Seimeitai?) 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 a cure 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 in order to enlist him in his plan to conquer the world. Initially, Shadow worked with him but secretly sought to destroy the planet in order to avenge Maria, who had been killed by the military, but was persuaded to save it from Gerald's doomsday plans. In the process, Shadow lost his memories and as such, sought to uncover the truth of his past, during which he met Black Doom and the Black Arms; in the end, Shadow regained his memories, uncovered the truth, and thwarted Black Doom's agenda and saved the world. From there, he continued his mission to protect humanity for the sake of Maria.
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.
- 1 Concept and creation
- 2 Appearance
- 3 Personality
- 4 Powers and abilities
- 5 Weaknesses
- 6 Relationships
- 6.1 Gerald Robotnik
- 6.2 Maria Robotnik
- 6.3 Doctor Eggman
- 6.4 Sonic the Hedgehog
- 6.5 Rouge the Bat
- 6.6 E-123 Omega
- 6.7 Black Doom
- 6.8 Mephiles the Dark
- 6.9 Silver the Hedgehog
- 6.10 Humanity
- 6.11 Miles "Tails" Prower
- 6.12 Knuckles the Echidna
- 6.13 Amy Rose
- 6.14 The Commander
- 6.15 Metal Sonic
- 6.16 Team Chaotix
- 6.17 Infinite
- 6.18 Friends/allies
- 6.19 Rivals
- 6.20 Enemies
- 7 References
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. 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 the idea Shadow, coming up with the idea to use a dark, anti-hero figure who was similar to Sonic in shape, but not in personality. While creating Shadow, there was a proposal to create a character that was as cool as or better than Sonic. Several early designs of Shadow ranged from having long spines with tufts of fur in front of his eyes, to having capes, shades or even a missing eye. Shiro Maekawa was the one who came up with Shadow's final design, and considers himself to be Shadow's creator. He states that there are times where he feels a stronger bond with Shadow than his real relatives.
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. According to Kazuyuki Hoshino, Shadow's red stripes were inspired by Kabuki makeup.
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 in the first game trailer for Sonic Adventure 2; however, his name was not revealed. GameSpot 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."
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.
Shadow is a black-furred anthropomorphic hedgehog. He has red eyes, a patch of white fur on his chest, a tan muzzle, and tan ear canals. He also has six quills on his head, four of which curve upwards while the other two curve downwards, two spines on his back, and a small tail. He has red stripes on each of his head quills, around the edges of his eyes, and on his arms and legs.
For attire, Shadow wears white gloves with black cuffs and red tongues, and Air Shoes which, like his gloves, have black cuffs and red tongues. Shadow also wears Inhibitor Rings, one on each of his wrists and ankles.
In the Sonic Riders series, Shadow wears green sunglasses on his head and shoes similar to his Air Shoes.
Being Sonic's polar opposite personality-wise, Shadow is, bluntly put, a brooding loner. He usually acts with a cool and businesslike indifference, only occasionally showing his vulnerable side. He is rarely seen with others for an extended period of time and usually distances himself from essentially everyone. He is usually blunt and does not speak much, but he always knows exactly what to say in combat. However, Shadow never bluffs; if he makes a threat, he has every intention of carrying it out.
Shadow also does not mind boasting about how powerful he is, calling himself the "Ultimate Lifeform" and, like Sonic, can be extremely arrogant, often belittling his opponents and insulting their lack of strength. He believes no one can beat him and tends to see anyone as a fool for challenging him. Shadow also has a ruthless and merciless edge in combat that most other characters in the series lack and displays a natural "killer instinct".
As the most violent and merciless character in the series at times, Shadow's ruthlessness and aggression leads to enemies never treating him lightly; he is one of the very few individuals Sonic takes seriously. 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 is and not caring for whatever the response is. Shadow is also shown to have a sharp wit; in Sonic Adventure 2, after being called a faker by Sonic, he replies that Sonic is not worth being considered his fake. In Shadow the Hedgehog, he similarly taunts Black Doom's eye for having trouble with GUN. This attitude is reflected in the original Japanese version, where Shadow omits honorifics and speaks highly of himself (if not rudely). At the same time, however, in Japanese, he normally uses the "boku" pronoun when referring to himself as opposed to the more arrogant/confident "ore" pronoun (which characters such as Sonic and Knuckles use).
Just like how Shadow's motivations are never simple to understand, he spends as much time grappling with his own inner demons as he does with his rival, Sonic. In the past, Shadow has had a degree of mental instability, in particular post traumatic stress disorder. This was 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 the instances of the latter game were simply an effect of his amnesia. On one occasion, in Sonic Adventure 2, seeing police sirens flashing caused him to intensely flash back to the massacre aboard ARK and in particular Maria's death. Shadow was soon able to overcome this in his his own game and in Sonic Battle, during which he chose to move on from the past, yet keep Maria in his heart. In fact, his personal journey since being awoken by Eggman has had him confront the shackles of his past, such as ties, fate, and memories. Since then, it appears as though he is reaching a point where he can "do as his heart desires" in his own way.
In many games Shadow is featured in, he pursues his foes with a relentless, unwavering determination. He will usually go to any length to accomplish something he desires or feels should be a certain way, no matter what the cost. In Sonic Forces, it is heavily implied that Shadow ruthlessly massacred an entire mercenary band not only in an extremely dismissive, nonchalant manner (as he did not even remember the incident a few months later), but also seemed slightly proud, mocking the mercenary defense squad by saying they themselves needed a defense squad. He also demonstrated rather coarse language in his own game.
Shadow possesses a strong sense of identity; after falsely being told by Rouge that he isn't the Ultimate Lifeform due to a lab report, he states to her 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 others.
In Shadow's own words, he is not interested in peace, nor does he care about what happens to others. In truth, he simply does not like when foolish people do whatever they please. While this may make it seem like Shadow stands firmly in opposition to villainy, he is actually very indiscriminate about who he faces, as he choses to stand against anyone who he condemns for being foolish, be they villains like Dr. Eggman or heroes like Sonic. He similarly does not want thanks for the help he provides when he does something heroic, believing that showing gratitude is a waste of time. Despite his apathetic nature, however, Shadow is not without compassion; since reforming himself at the end of the Space Colony ARK incident, he has ultimately fought for the greater good. When Omega begins his attack in Sonic Heroes, Shadow could have easily forgotten about Rouge and engaged Omega without defending her, but instead 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 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. In Sonic Colors, Shadow was also shown to be worried about the possibility of Sonic and Tails getting hurt while trying to save the Wisp, much to their surprise. However, he ultimately remained dismissive about his concern for them.
Shadow is often depressed about the loss of Maria, which is why he keeps to himself, but his relationship with Maria is obvious as he goes to great lengths to protect the planet and keep her dream of peace and prosperity alive. He also maintains a strong bond with his teammates, Rouge and Omega, proving that while his attitude makes him seem like a careless person, he does have some compassion, more than he otherwise lets on. Still, Shadow brushes off most kindness or sympathy that is sent his way; in Sonic Heroes, when Rouge showed concern for Shadow when he saw a broken android of himself, suspecting Team Dark's Shadow might be an android too, Shadow curtly brushed her concern away. In Shadow the Hedgehog, after Sonic suggested some "friendly competition," Shadow bluntly rejected his offer. At times, however, Shadow is shown to appreciate genuine care. In Sonic Adventure 2, after Amy made him remember his promise to Maria, Shadow openly decided to keep his promise to protect the planet both to Maria and her. Another instance is in Sonic the Hedgehog (2006), when Rouge told him that she would always be by his side, he acknowledged her.
Despite the fact that Shadow often fights for the greater good, he is considered an anti-hero for the most part due to his morality and means to his desired end goals. 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. Alongside Rouge, he has also taken prize money and jewels upon winning in Sonic Free Riders. He and Rouge disregard the opening and closing ceremonies for the Grand Prix, showing up late without a third teammate and, if they win the Grand Prix, starting to walk off right away with what turn out to be dummy versions of the prize money and gems. Regardless, Shadow does have his moments of selflessness and heroism; he nearly sacrificed 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 him in Sonic the Hedgehog (2006).
Powers and abilities
Said to be Sonic the Hedgehog's equal in almost every ability, Shadow can easily rival Sonic's various physical skills. His abilities and skills in combat are an extremely powerful force to be reckoned with, and he is a match for even the most powerful foes in the series. He similarly never willingly holds back his immense strength, making him a brutal fighter. On his own, Shadow has been able to take down GUN's various combat mechs, Dr. Eggman's battle robots, Black Doom and his empowered state, and even deities. To best put his skills into perspective, Shadow was capable of defeating even Sonic while he had Diablon for support, as seen in some of the scenarios during the Black Arms incident. He even managed to best Emerl in combat after the latter had acquired all seven Chaos Emeralds as a power source (although Emerl quickly surpassed him afterward).
Like many of his associates, Shadow is able to move at super speed. Said to possess "ultimate speed", Shadow is able to match the speeds reached by Sonic, who is able to reach hypersonic speeds. Although Shadow's Air Shoes have been credited as the source of his speed, his powerful body allows him to easily rival Sonic's world class speed as well. Due to such speed, he can scale vertical surfaces and ceilings, out-speed bullets, and attack faster than the eye can see. Even then, Shadow can take his speed even further; by envelope himself in a red energy field, he can accelerate beyond the sound barrier on both the ground and in midair for a short time, allowing him to not only smash straight through enemies and obstacles like a living projectile, but also fly immense distances through midair. Using certain techniques, he can even achieve light-speed momentarily. While there are some inconsistencies about how fast Shadow is compared to Sonic, it is usually stated that they are complete equals. Shadow has demonstrated complete mastery of his speed in any environment. Not only can he run at maximum tilt in straight lines, but also in full tight circles and through sharp turns with full control over his momentum. As far as stamina goes, Shadow's is seemingly limitless as he is never winded from running. His speed also allows him to perform several impressive feats, like spinning in circles or rotating his extremities at super speed to create winds strong enough to attack or blow away/suck in opponents, similar to aerokinesis.
An experienced athlete that shares Sonic's agility, Shadow has outstanding acrobatic skills and nimbleness, along with incredible reflexes that let him avoid any incoming obstacles with precise and delicate movements within split-seconds, grind expertly on Grind Rails, dodge bullets, and perform various strafe movements. When launched into the air, he can also pull off several tricks before landing. Shadow also has superhuman strength, enough to match Sonic in power; with effort, he can overturn objects many times his weight and size such as trucks, buses and large slabs of concrete with one hand. In addition, Shadow possesses astounding kineticism, precision and has reaction time to match his speed. Shadow also has an incredible resilience to damage as he can take lots of major punishment before he goes down for the count. Notably, he is completely bulletproof and even withstood atmospheric entry at the end of the Space Colony ARK incident (the latter which only left him with amnesia). Even when he takes damage though, he is able to recover rather fast.
Owning to his "ultimate life form" physiology, Shadow possesses an immortal body and does not age. Furthermore, as seen during the Black Arms incident, due to being partly Black Arms, Shadow has a connection to the Black Arms' hive-mind, allowing him to sense his kind's presence and be immune to the Black Arms' body-paralyzing nerve gas.
Shadow also possesses an indominable will and determination. His absolute refusal to give up in any situation and resolve to see his goals through to the end allows him to keep on perservering even in seemingly impossible situations. His enormous will even lets him psychologically resist mind control powers; notably, Shadow was able to regain control of his body from Black Doom despite him being part Black Arms and therefore susceptible to Black Doom's mind control.
Shadow is naturally able to tap into the arcane powers of nearby Chaos Emeralds, either through physical contact or from a distance, to empower himself and access different chaos powers. According to Shadow himself, he is the only one who knowns how to use the Chaos Emeralds' true power. His trademark ability in the field of chaos powers is Chaos Control, an technique achieved with the Chaos Emeralds that lets him warp time and space for various effects. With this technique giving him control over time and space, Shadow is able to warp himself and those close by across space instantaneously over a range further than an island-annihilating explosion or between dimensions, slow down or freeze time entirely, and create areas of distorted space. Shadow is noticeably adept in using Chaos Control for anything between large-scale usages to small-scaled and delicate chaos powers inside and outside of combat. He can for example use it to either freeze or slow down opponents in time to give himself the speed advantage, launch surprise attacks by suddenly warping up in front or behind opponents, distort space around his fists for strikes that can blow opponents away, hide himself away in distorted space, attack foes with spots of distorted space, and even power his own healing abilities and guarding skills. Typically however, Shadow cannot perform Chaos Control if he does not have any Chaos Emeralds to draw power from.
Beside Chaos Control, Shadow is able to use a number of additional chaos powers. One of these chaos powers include his Chaos Spear technique, in which he throws up to several bolts of chaos energy at his opponent that can either paralyze or injure an opponent, depending on its power level. Shadow's most powerful technique, however, is the Chaos Blast, a chaos power where he releases a discharge of chaos energy in a massive explosion that eliminates everything within a range of 10-20 yards.
One of Shadow's main offensive maneuvers is the Spin Attack, a technique where he curls into a concussive ball or cutting disk and directs himself at his targets. With it, Shadow can shred or burrow through just about any substance given enough speed. Highly adept in its usage, Shadow can utilize several variants of the Spin Attack for both grounded and aerial maneuvers, including the Spin Dash, Spin Jump, Homing Attack, and the Light Speed Attack, which attacks at the speed of light.
Even without his Spin Attack, Shadow is a powerful hand-to-hand combatant. In line with his nature and potent abilities, Shadow uses a fighting style where he utilizes strong blows, such as powerful chops, high spin kicks, reverse spin kicks, downwards kicks, or just barrages of punches and kicks. In addition, many of Shadow's stronger hand-to-hand combat moves revolves heavily around his usage of Chaos Control for distortion effects to knock opponents away and his Air Shoes' exhaust for burning opponents.
As shown during the second EX Grand Prix, Shadow is talented with an Extreme Gear. During the tournament, 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 Grind Rails, execute complex tricks while in midair, and perform chaos powers and combat moves with ease.
Shadow also has extraordinary skill when it comes to driving or piloting all forms of vehicles. Not only is he one of the best racecar drivers in the universe with the Dark Reaper, but he is also able to perfectly operate weaponized buggies, armed motorcycles, modified gliders, hover crafts with machine guns, bipedal mechs and alien devices. Shadow is as well an expert gunner, capable of using weaponry like the Gun Lifts and GUN turrets with perfect accuracy. Also, whereas Sonic dismisses firearms, Shadow is not above using such weaponry, and has demonstrates proficient skills in a very wide range of weapons during the Black Arms incident, such as close combat weapons, guns, cannons, lock-on weapons and lasers. Shadow may also have some knowledge about machinery, having once been able to fiddle with a deactivated Omega and deduce he was in standby mode. A miscellaneous ability Shadow has demonstrated as well is telekinesis, which is potent enough to let him move an Extreme Gear around with his mind with ease.
As powerful as he is, Shadow is able to make himself stronger up tapping into an even greater power within himself. This power is so potent that should he remove his Inhibitor Rings, he becomes a walking dynamo of raw power. When unleashing this power, he releases such tremendous amounts of energy that it forms an impenetrable barrier around himself. While in this state, Shadow gains increased strength and speed, enough to overpower hundreds of clones of Mephiles the Dark at once. However, using his full power tires him out more quickly.
Shadow wears a pair of specialized shoes called Air Shoes. These footwear are the primary source of Shadow's speed, producing small jet streams that let him hover-skate at speeds supposedly even surpassing Sonic's speed. Alternatively, Shadow can use his Air Shoes' exhausts to attack opponents with fire, empower his jumps, or achieve midair hovering.
Shadow wears four Inhibitor Rings, one on each of his wrists and ankles, that limit the amount of power he uses during combat and other situations. By removing them, Shadow is able to utilize his full power.
During the Black Arms incident, Shadow made use of a vast selection of weaponry. This included anything from close combat weapons like Survival Knives and Black Swords, to guns like Pistols and Sub-Machine Guns, to cannons like Bazookas and Grenade Launchers, to lock-ons like 8-Shot RPGs and Worm Shooters, to lasers like Laser Rifles and Refractors.
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 surpass his normal ones and his chaos powers are increased to their full limit. He is also 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. In addition, this transformation consumes a lot of energy, meaning it cannot be maintained for long.
When his mind is fueled by thoughts of justice, Shadow is able to attain an enhanced state known as Hero Shadow. In this state, Shadow is temporarily invincible and can perform a large-scale use of Chaos Control. However, this state only lasts for a short period of time.
When his mind is fueled by thoughts of evil, Shadow is able to attain an enhanced state known as Dark Shadow. In this state, Shadow is temporarily invincible and can perform a large scale-use of Chaos Blast. However, this state only lasts for a short period of time.
On his own, Shadow can access an enhanced state known as the Chaos Boost. In this state, Shadow's powers are boosted significantly, granting him warp-like speeds, near invulnerability, and bolstered chaos 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.
While not having any physical weaknesses, Shadow was initially a somewhat easy target for manipulation during the time he had amnesia due to his confusion about who he was and his eagerness to learn anything more about his past. Dr. Eggman could deceive him with lies about his past and Black Doom could subtly manipulate him using visions. Similarly, it is heavily implied that the reason he thought Maria's last wish was revenge against humanity was that Gerald Robotnik implanted false memories of her death. However, after learning of his true purpose, Shadow was no longer as easily deceived.
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.
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 outcome 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 proven when Gerald refers to the hedgehog as his "son," having given Shadow genuine emotions to prevent him from becoming a weapon as the government intended. However, despite these predisposed emotions, after 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.
In the Last Story of Shadow the Hedgehog, Shadow finally uncovered the true purpose of his creation from Gerald's recorded video. And in order to put the past behind him, he decided to fulfill Gerald's true wish of protecting the planet by destroying the Black Arms and any future threats that may come Earth's way.
Professor Gerald's granddaughter, Maria Robotnik, is by far the one person that made Shadow the happiest. Shadow and Maria bonded closely during their time together; Shadow's feelings for Maria were the closest he ever came to love. Maria seemed to be a guiding force in Shadow's life, doing her best to erase any doubts he had about the purpose of his existence. They shared the same dream: to visit earth together someday.
Unfortunately, G.U.N. deemed Project Shadow to be too big a threat to the world. As a result, they attempted to eliminate everyone and everything they could in relation to the project. Maria was shot and killed by a G.U.N. soldier during the raid on the ARK. Her parting words were "Sayonara, Shadow the Hedgehog."
In a 1UP interview, Shadow has stated that if he could change one thing about his past, it would be to give up his life for that of Maria's. He is forever haunted of losing someone that really cared for him. Despite his grief, Shadow stays strong and continues to keep his promise to her, to make the people of earth happy.
After getting amnesia, Maria was the only thing that Shadow could really remember. At the end of Shadow the Hedgehog, he implies that he is putting his past behind him, though he continues to save the world in her name.
Shadow has had a complicated past with Eggman. Currently, the pair are enemies and have opposed each other at several points. However, Shadow's approach to Eggman has differed slightly from most characters in the Sonic series. Shadow once saw Eggman as a super-genius, rather than a megalomaniac. This can be backed up by the fact that Shadow usually calls Eggman by the title of "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 have displayed a level of respect toward each other, they also exhibit disdain toward one another. This can be backed up in Sonic the Hedgehog (2006), 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". The pair do not regard each other as anything more than acquaintances at best, enemies at worst.
In Sonic Forces, it seems that Shadow and Eggman are completely enemies, as Shadow attacks an installation of Eggman while the doctor wants to see Shadow destroyed.
Sonic the Hedgehog
Shadow and Sonic are rivals and allies. At first Shadow tried to disregard Sonic, but Sonic's quips quickly sparked a mutual rivalry in Sonic Adventure 2. Throughout the game, the feats Sonic accomplishes, such as surviving Eggman's death trap and learning Chaos Control, impressed Shadow, and he began to respect Sonic, giving him his props before the final battle between them. Since meeting each other, their rivalry has developed, and while it is now usually friendly, the two can still occasionally be at odds.
When they first met, Shadow believed Sonic to have been copying him, and vice-versa from Sonic. He at first had this belief in Sonic Heroes, largely because of his amnesia.
Shadow and Sonic's conflicts tend to occur due to the fact that even though their goals tend to align, their views on justice, morality, and how to act on them can sometimes differ. Their disagreements sometimes turn to bitter fights. In a sense, the two hedgehogs are polar opposites in every way except their appearance and goals. 
Despite their differences, Shadow and Sonic have helped each other on several occasions. Shadow helped Sonic defeat Metal Sonic in Sonic Heroes, allied himself and Rouge with Team Sonic to return both teams to their proper time period, and saved the blue hedgehog from Silver's second attempt on his life in Sonic the Hedgehog (2006). He showed grief in the face of Sonic's death and stated that they cannot defeat Solaris without his help. In the Nintendo DS version of Sonic Colors he clearly shows some concern for Sonic's safety. Additionally, he helped motivate Sonic to defeat the Time Eater in Sonic Generations and attended his birthday party. He even raced to help out Sonic in Sonic Forces at the beginning of the game, but was unfortunately too late. He later succeeded in saving Sonic from a replica of himself in Sunset Heights despite the blue hedgehog's initial suspicions about the situation. Nonetheless, Shadow did participate in fighting alongside the hedgehog for the rest of the war. Overall, while the two still are at odds because of their conflicting views, there is also a mutual respect between them. They are both willing to put their differences aside and help each other when needed. In recent games, Shadow is more confident about Sonic doing what is right and Sonic has more faith in Shadow's abilities as well.
On a similar note, he also has some distaste for being confused with Sonic, as evidenced by his fierce reaction to Toad mistaking him for the latter in the Adventure Mode of the Nintendo DS version's Mario & Sonic at the Olympic Winter Games and Mario & Sonic at the Rio 2016 Olympic Games, where interacting with Shadow as a Mii character in the latter game will have Shadow react irritably towards the Mii character noting his physical resemblance with Sonic, and demand that the Mii character not ever put him on the same boat as Sonic, whom he referred to as an "inferior half-wit."
If there is one thing that can be said about Shadow and Sonic, it is that they are rare ones who can get up close and personal with each other. Because of the high performance of both Shadow and Sonic in terms of their physical abilities and their thoughts, there are not many who can keep up with them. Also, there are fewer still of the ones who, despite their rejection, are able to persist, to offer opinions, to meddle, or to stand in their way and try to stop each other like those two can. In fact, Sonic is perhaps the only person who can get so up close and personal with Shadow as he can and say something to him that reaches his heart (though it often does not). In a sense, Sonic's kind of presence is troublesome to Shadow, but it is also one of the most important ones. However, while Sonic is receptive to hearing things that strike a little close to home, from Shadow's point of view, Sonic is a real pain. Regardless of much of an impact they each have on each other, the two of them both share the philosophy of following their hearts' desires, which makes them colliding with each other, crossing paths with each other, and sometimes dividing into friend and foe.
Rouge the Bat
Rouge the Bat is one of Shadow's closest companions. The two are teammates in Sonic Adventure 2 and Sonic Heroes, and they often work together during mission stages. Despite the fact that the pair have not casually spent much time together, they still greatly appreciate and respect one another. Rouge and Omega are shown to be the two who Shadow cares about and appreciates the most. Rouge is certainly one of, if not the closest person for Shadow to interact with. 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 is 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. Later, when Rouge mentioned intending to steal Knuckles' Master Emerald, Shadow replied that "things never change, do they?", implying that he regained enough of his memory to remember her rivalry with Knuckles' Master Emerald.
In Sonic Battle, Rouge lets Shadow stay with her at Club Rouge when he is injured during a fight at the Gimme Shelter. When Shadow is dreaming and an image of Rouge appears and he whispers, "Ally." After he regains consciousness Rouge seems somewhat offended when he does not thank her for helping him. Upon finding out she saved him, Shadow thanks her.
In Sonic the Hedgehog, Shadow shows he is protective of Rouge's well-being. He showed this 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 Omegs 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." Nonetheless, it is implied in Sonic Forces that she ultimately stayed true to that claim and maintained contact with Shadow while he was still assumed to have gone rogue due to his replica. This is evidenced by how, when, reconvening with Rouge, he asks her about whether she found what he had requested earlier.
In Sonic Rivals, after Shadow saves Rouge from Eggman Nega, Rouge tries to convince him to 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. Shadow is consistently trying to stop Rouge and Knuckles from reaching the Chaos Emeralds at all costs, seeking to manipulate the Chaos-tracking device from Rouge. Rouge tells Shadow that he 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, proving that although they may be on good terms sometimes, that does not mean that they let each other get in the way of their goals.
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.
Shadow has been known to trust Omega as a partner in his missions, though with a mutual understanding of both of them being seen as weapons used for destruction. However, their relationship goes beyond their seemingly gruff, aloof, and mighty exteriors, revealing a trusting, mutual friendship between the two. 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, Shadow is the one who first spots the deactivated Omega, 200 years into the future. Shadow shows real sadness as the sight of this, as Rouge has to force him to continue moving. 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.
Though Sonic Chronicles: The Dark Brotherhood is not considered to be a canon game, Shadow and Omega appear to have a much closer relationship in it. Shadow joins Sonic's team to find Omega, he clearly shows anger if the player refuses to rescue him and states that if something has happened Omega, then he will "be very upset." He also states that "he was also my friend" which shows how much he cares for his wellbeing, as this is the first time that Shadow openly admits that Omega is his friend. 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."
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 constantly follows Shadow throughout the game, trying to get him to see what he believed to be the truth about humanity and that they needed to be punished. Even after Shadow opposes him several times, Black Doom will still insist on trying to get Shadow to join him, turn on humanity and see things his way. 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 cares nothing about him and is only interested in his power. He also shows strong disapproval and demands extreme loyalty and respect from him, especially when he shows opposition to 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 an end to his biological father and his "offspring" after learning of the nature of his plans.
Mephiles the Dark
Mephiles the Dark is one of Shadow's deadliest enemies. When they first met, Shadow, due to not having sealed Mephiles away yet at that time, expressed a sense of familiarity despite not knowing who he was, before Mephiles sent him to the future. In Shadow's second meeting with Mephiles, he tried to convince Shadow to turn 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 realize 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 him by asking why he wanted to save humanity when they would persecute him, but Shadow proclaimed he would always keep fighting. Solaris and Mephiles were both later erased from existence, resulting in the erasure of Shadow's relationship with Mephiles.
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 attempting Chaos Control on each other, which Shadow was impressed by, the black hedgehog told the misguided Silver that Mephiles was using him for his own ends. To get their answers, the two traveled back ten years to witness the Solaris Project accident. They 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, where they then use Chaos Control to return to the present. They meet up once more 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.
Initially, Shadow did not hate humanity 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 against 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 humanity, 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 humanity had brought him to turn him against them. However, when Shadow regained his memories as Black Doom unveiled his plans to eradicate humanity by using them as food for his kind, Shadow once again chose to save humanity to keep his promise to Maria and stay true to his purpose.
While Shadow still holds a general loathing of humanity, he has made it his mission to protect them due to his promise to Maria. He has as well gained his own desire to bring hope to humanity, though he has misgivings about humanity's fear of his power and viewing him as dangerous in spite of this. In all his encounters with Mephiles in Sonic the Hedgehog (2006), who attempted to make Shadow turn on humanity 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 proclaimed that if someday the world chooses to become his enemy, then he will fight it, showing that it is up to humanity to decide whether he is their enemy or not.
Miles "Tails" Prower
Miles "Tails" Prower and Shadow were at first enemies in Sonic Adventure 2 because Shadow was impersonating Sonic and got him thrown in jail at Prison Island. Towards the end of the game, they became allies when they had to save the planet from the Space Colony ARK. For the most part Shadow and Tails' relationship seems to depend on their goals.
The two are on opposing sides in Sonic Heroes, Sonic Battle, and Sonic Rivals 2. In Sonic Heroes they fought very briefly because Shadow and Rouge had provoked Team Sonic into fighting them. In Sonic Battle, Shadow and Tails fought at the end of Tails' Story because Tails resisted giving up Emerl to Shadow. Shadow threatened Tails that he would have to give Emerl up or else they would fight for him, Tails admitted that he admires Shadow's spirit but would not give up in a fight. When Tails won the fight Shadow warned him that he would be back again to get Emerl, but Rouge showed up and told Shadow to go back to Night Babylon. In Sonic Rivals 2. Shadow and Metal Sonic confronted Tails and Sonic because they were all going after Eggman.
However despite this, Shadow and Tails seem to be on very good terms with each other, and seem to get along quite well. Also, when Eggman suggests they build a weapon to hurt the enemy, and Tails says he has a better idea, Shadow with a smile asks why he is not surprised. Shadow is actually the second most helpful member of Tails' Team in Metropolis, helping Tails with numerous mechanical ideas with Eggman. He is also very helpful if the player is looking for Omega, often giving tips to tell of where Omega would have gone if he had gotten the chance. If the player succeeds in finding Omega, Shadow thanks Tails for helping him. Overall, Shadow and Tails hold a great deal of mutual respect for each other, and despite being occasional enemies, they seem to support each other, and they have helped each other on several occasions.
Knuckles the Echidna
Shadow and Knuckles have not interacted much, but at times they are either allies or rivals. In Sonic Adventure 2, they didn't have much interaction, but they were enemies at 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 they might have 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 (2006), he and Shadow loosely worked together again for a time in order to return to the present.
Shadow and Knuckles appear to have some bitter resentment towards each other as seen in Sonic Rivals, when Shadow bluntly pointed out that Knuckles was useless for his shortcomings while retaining an indifferent attitude towards his challenges, and Knuckles seemed to be irritated by Shadow's presence. Knuckles seems to have a bit of a disliking towards Shadow, mostly because he thinks that he is complacent and smug. Additionally, Knuckles is not fond of Shadow's egotistical tendencies, which is seen in Sonic Free Riders when he says "I see your ego's as big as ever, Shadow.", in a rather annoyed tone.
Shadow and Amy have not interacted much with each other throughout the series. In Sonic Adventure 2, 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 begs 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.
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 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.
The Commander and Shadow were enemies because the Commander blamed Shadow for the death of his family and Maria fifty years ago during the G.U.N. raid on the ARK. 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 his house to see his new grandchild; this is presumably the time that Shadow became a G.U.N. agent.
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 States. 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. Shadow's concern may be due to the similar partnership he had with Omega. 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 Shadow, 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.
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. Team 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 did not want to hear it. Espio has shown his capacity of comradery with 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.
Shadow first encountered Infinite back when he was known as the Ultimate Mercenary after decimating the Jackal Squad group he led. Although the Ultimate Mercenary expressed confidence that he could beat Shadow with his own abilities, Shadow promptly proved him wrong by easily beating him before the latter could get a chance to fight back, leaving the mercenary terrified. Shadow was less than impressed with the Ultimate Mercenary during this time, bluntly and rudely telling him that he was worthless, as well as telling him not to show "[his] pathetic face" towards him ever again before taking his leave. Little did Shadow know, however, that this would ultimately prove to have serious ramifications months later, when the Ultimate Mercenary proceeded to fuse with the Phantom Ruby to become stronger.
Several months later, he encountered Infinite, who reminded Shadow (who had already forgotten who he was) of their earlier encounter, and then proceeded to fully demonstrate his new abilities by trapping him within a Virtual Reality world via the Phantom Ruby. The encounter left Shadow shaken, as well as disturbed by Infinite's letting slip of his intention to defeat Sonic.
- Rouge the Bat (partner)
- E-123 Omega (partner)
- E-10000B (formerly)
- Sonic the Hedgehog
- Miles "Tails" Prower
- Knuckles the Echidna
- Amy Rose
- Cream the Rabbit
- Big the Cat
- Team Chaotix
- Silver the Hedgehog
- Blaze the Cat
- Maria Robotnik (best friend)
- Gerald Robotnik
- The President
- The Commander
- Classic Sonic
- Dodon Pa
- Eggman Empire
- Black Arms
- Mephiles the Dark
- Dr. Eggman Nega
- Metal Sonic 3.0
- The Babylon Rogues
- Nocturnus Clan
- Jackal Squad
- Creators Interview 006: Maekawa Shiro. Windii. Pastebin (22 June 2018). Retrieved on 12 January 2019.
- Fast talking. Archived from the original on 26 June 2009. Retrieved on 4 September 2016.
- Ryan Drummond on Twitter. Twitter (15 October 2020). Archived from the original on 15 October 2020.
- Devra Newberger Speregen (2016). Sonic: The Ultimate Character Guide. Scholastic. p. 31. ISBN 978-1338033243.
- Sonic City. Sega. Archived from the original on 29 February 2008.
- Sega. Sonic Channel (Japanese). Characters: Shadow. Archived from the original on 26 May 2019. Retrieved on 3 July 2015.
- Sumo Digital (23 February 2010). Sonic & Sega All-Stars Racing. PlayStation 3. Sega. Area/Level: Shadow the Hedgehog's profile card.
- Sega of America. Shadow the Hedgehog. Sonic Characters. Sega of America. Archived from the original on 5 March 2005. Retrieved on 26 October 2017. "Shadow is the spitting image of sonic except for his black body. The world's greatest scientist, Professor Gerald, created him for a purpose known only to the professor. Ageless and immortal, Shadow has the special ability to harness the power of the Chaos Emerald, which allows him to warp time and space. Sharp-witted and willing to do whatever it takes to get what he wants, he always seems to be on the edge. Maria, who was raised with Shadow and was Maria's only friend, died in front of his very eyes. Her final wish was that Shadow save the world. Saving the world from what is a secret only Shadow knows. Traumatized by the grief of her death, Shadow remains strong enough to keep the promise he made to her."
- ソニックステーションLIVE！ with 悠木碧（2021.3.21放送回） (Japanese). YouTube. ソニック・ザ・ヘッジホッグ【公式】 (21 March 2021). Retrieved on 11 July 2021.
- Sonic Adventure 2 Hands-On. GameSpot.com. Retrieved on 2019-12-02.
- "The Shadow character idea was something that we all had in our minds in the dev team when we were creating the first Sonic Adventure. When creating that game, we had the intention of creating a rival character for Sonic Adventure 2 and we didn't really talk about it that much, but we were all thinking about it. When we were working on Sonic Adventure 2, we all did a bit of brainstorming and we brought this to the table and prepared the storyline for the Dark side and the Hero side. As you know in the story, Shadow was only meant to appear in that single title. But because of the reaction of the fans, we decided to bring him back in Sonic Heroes and eventually you saw him in his own title." - Takashi Iizuka at Summer Of Sonic 2011
- Shadowing a Hedgehog. Yahoo.com. Retrieved on 2008-12-16.
- Shadow the Wrestling Hedgehog. 1up.com. Retrieved on 2009-01-26.
- Sega's Yuji Naka Talks!. GameSpy.com. Retrieved on 2008-07-11.
- Sega (28 June 2021). ソニック & シャドウ (Japanese). Sonic Channel. Archived from the original on 28 June 2021. Retrieved on 28 June 2021.
- Pedigree Books (August 2013). "Eggman's IQ Math Test". Sonic the Hedgehog Super Interactive Annual 2014. Pedigree Publishers. p. 15. ISBN 978-1908152077. "Fact: Shadow often launches into situations without fully thinking them through. That natural enthusiasm sees him take risks and dabble with danger as he tries to get what he wants, by any means necessary."
- Sonic Team, Dimps (12 November 2010). Sonic Colors. Nintendo DS. Sega. Area/Level: Asteroid Coaster. "Shadow: I'm happy to leave the racing around all day to them, thanks. / E-123 Omega: Unable to process. According to data, your ability equals Sonic's."
- Super Smash Bros. Brawl (2008). In-game description of the "Shadow " trophy. "Shadow the Hedgehog is a black hedgehog who resembles Sonic. He was created by Dr. Eggman's grandfather, Gerald Robotnik, to be the ultimate life-form. Not only does he look like Sonic, but he has equal abilities. He has great skill with the space-time warping technique called Chaos Control. To reach his goals, he'll use any means necessary."
- "Matching his great rival Sonic in almost every regard, Shadow is out to prove he's the ultimate competitor." - Mario & Sonic at the Sochi 2014 Olympic Winter Games website.
- Sonic & Sega All-Stars Racing (PlayStation 3) United Kingdom instruction booklet, pg. 5.
- Sonic Team (4 November 2011). Sonic Generations. PlayStation 3. Sega. Area/Level: Collection Room. "Shadow's character profile: Created as the "Ultimate Life Form" by Professor Gerald Robotnik, Dr, Eggman's grandfather, Shadow is the spitting image of Sonic, sharing his agility and speed. He has a strong sense of purpose and pursues his goals by any means necessary."
- Sonic Heroes (PlayStation 2) United States instruction booklet, pg. 8.
- Sonic Team (27 February 2004). Sonic Battle. Game Boy Advance. Sega. Area/Level: Gimme Shelter (Shadow's Episode).
- Sonic Battle (Game Boy Advance) United States instruction booklet, pg. 4.
- Sonic Heroes official website. Characters: Team Dark. Sega. Retrieved on 24 June 2004. "Shadow is the dark incarnation of Sonic, created by the renowned scientist, Professor Gerald at the height of his career. This black hedgehog matches Sonic's great speed and skills and has the ability to distort time and space using "Chaos Control." Shadow was presumed dead after his fall at Colony Arc in Sonic Adventure 2 Battle, but Rouge discovered him hidden away at Dr. Eggman's base. He has no memory of what happened to him but he's anxious to track down Dr. Eggman and find out."
- Sonic Adventure (Dreamcast) United States instruction manual, p. 18.
- Sonic Rivals 2 (PlayStation Portable) United States instruction booklet, pg. 8.
- Sumo Digital (23 February 2010). Sonic & Sega All-Stars Racing. PlayStation 3. Sega. Area/Level: Character Select screen. "Shadow the Hedgehog's profile card: Shadow is an artificial life form, created by Dr. Eggman's grandfather. His initial hatred of Sonic has now developed into a friendly rivalry. Like Sonic, Shadow is about speed – his acceleration and “Spin Attack” coming from his rocket skates. With Chaos Emeralds he can power up his Chaos Control and warp time and space. If he has all seven emeralds he can transform into Super Shadow – which, like Sonic, makes him invulnerable and gives him run-flight. Shadow uses a modified G.U.N. motorcycle known as the Dark Rider."
- Shadow the Hedgehog (Nintendo GameCube) United States instruction booklet, pg. 7.
- Sonic Team, Blindlight (14 November 2006). Sonic the Hedgehog. Xbox 360. Sega. Cutscene: Shadow's infiltration (Shadow Episode).
- Sega. Official Sonic Heroes website (Japanese). Characters: Team Dark. Sega. Archived from the original on 12 November 2004. Retrieved on 29 July 2015.
- Shadow the Hedgehog (Nintendo GameCube) United States instruction booklet, pg. 15.
- Sonic Team (15 November 2005). Shadow the Hedgehog. Nintendo GameCube. Sega. Area/Level: Cinematic intro.
- Sonic Team (15 November 2005). Shadow the Hedgehog. Nintendo GameCube. Sega. Area/Level: Devil Doom. "Dr. Eggman: Shadow, can you hear me? This might be the last chance I have to speak to you, so... what I said, about having created you? It was all a lie. Everyone thought you'd died during that horrible incident, but I rescued you with one of my robots! You'd lost your memory, that's all. You really are the Ultimate Lifeform my grandfather created!"
- Sonic Team, Blindlight (14 November 2006). Sonic the Hedgehog. Xbox 360. Sega. Cutscene: Omega appears (Shadow Episode).
- Mario and Sonic Tokyo. Main page. Sega. Archived from the original on 20 October 2020. Retrieved on 21 August 2019. "A black hedgehog known as the ultimate life form. Created with an immortal body, he wields Chaos Emeralds to warp space and time."
- Sonic Team (15 November 2005). Shadow the Hedgehog. Nintendo GameCube. Sega. Area/Level: Final Haunt. "Sonic: Once every 50 years, that Black Comet passes by this planet. Oh! Do you think those black creatures are somehow connected with that comet? / Shadow: Black ... Comet. UGH! / Sonic: Shadow! What's wrong?! / Shadow: I think you're right... I feel it... they're up there. That's where the answers are...I've got to get to that comet!"
- Sonic Team (15 November 2005). Shadow the Hedgehog. Nintendo GameCube. Sega. Area/Level: The Last Way. "Black Doom: Such bravado for a little hedgehog! I thought you were different from the rest... but maybe not. We are more alike than you think... the same blood runs through our veins. / Shadow: This can't be... Uugghh... Just... who are YOU? / Black Doom: Don't you know? You were created from my blood... / Shadow: Wha...what!? / Black Doom: That's right... You are a part of me... do you feel that? I can control you... You can cannot escape me... nor can you escape your past! Hahahahaha... / ... / Black Doom: Gerald.. you fool! Shadow is already in my control... What's this?! Well, well, well... seems like you're immune to my mind control. / Shadow: You have no control over me, Black Doom! I now understand why I am here... I made a promise and I'm here to keep it! Today, I put my past behind me!"
- Sonic Team (3 May 2002). Sonic Adventure 2: Battle. Nintendo GameCube. Sega. Area/Level: After the first battle with F-6t Big Foot (Hero story).
- Sonic Team (3 May 2002). Sonic Adventure 2: Battle. Nintendo GameCube. Sega. Area/Level: After the first battle with Sonic (Dark story).
- Sonic Team (27 February 2004). Sonic Battle. Game Boy Advance. Sega. Area/Level: Central City (Shadow's Episode). "Shadow: Hmph! The only one who can use the true power of the "Chaos Emeralds" is me."
- Sonic Adventure 2 (Dreamcast) United States instruction booklet, pg. 7.
- Sonic Team, Blindlight (24 November 2006). Sonic the Hedgehog. Xbox 360. Sega. Cutscene: 10 years ago (Shadow Episode). "Shadow: Don't bother. With a Chaos Emerald's power, I control time and space. You can't break free."
- Sega (13 November 2011). Mario & Sonic at the London 2012 Olympic Games. Wii. Sega. Area/Level: London Party. "Shy Guy: Do you know what Shadow's Chaos Control lets him do? [...] I hear he can stop time and move to another place in an instant!"
- Shadow the Hedgehog (Nintendo GameCube) United States instruction booklet, pg. 16.
- Sonic Team (27 February 2004). Sonic Battle. Game Boy Advance. Sega. "Chaos Magic: Shadow's ground shot. He hits his opponents with distorted space created with Chaos Control."
- Sonic Boom 2013 - Part 2/3 - Q&A Session (41:30). YouTube. MajinReid (13 August 2013). Retrieved on 26 May 2021. "Takashi Iizuka (as translated by the Q&A board's translator): If he [Shadow the Hedgehog] doesn't have a Chaos Emerald he cannot use Chaos Control"
- Sonic Team, Blindlight (14 November 2006). Sonic the Hedgehog. Xbox 360. Sega. Cutscene: Omega located (Shadow Episode).
- Sonic Riders
- Sonic Team, Blindlight (14 November 2006). Sonic the Hedgehog. Xbox 360. Sega. Cutscene: Showdown with Mephiles (Shadow Episode).
- Sega (11 November 2011). Mario & Sonic at the London 2012 Olympic Games. Wii. Sega. Area/Level: London Party. "Shy Guy: What does Shadow wear on his wrists and ankles? [Answer is revealed to be "Gold rings"] He's faster and stronger without the rings, but he gets worn out more quickly!"
- Sonic Team (27 February 2004). Sonic Battle. Game Boy Advance. Sega. "Shadow Run: Shadow's running skill. With help from his Air Shoes, he can run faster than Sonic."
- Sonic Team (3 May 2002). Sonic Adventure 2: Battle. Nintendo GameCube. Sega. Area/Level: Finalhazard. "Super Shadow: Gutha! I don't have enough energy to transform into my Super Form!"
- Sonic Team (20 December 2001). Sonic Adventure 2: Battle. Nintendo GameCube. Sega. Area/Level: Finalhazard. "Super Shadow: クゥッ…！どうやら、ボクの体にこのスーパー化は無理があったようだ…。 (Gah...! It seems impossible for my body to keep this Super form...)"
- Sonic Team (15 November 2005). Shadow the Hedgehog. Nintendo GameCube. Sega. Area/Level: Westopolis. "Sonic: The power of justice lets you use the teleport using Chaos Control. If you are fueled by evil though, you'll be able to unleash the destruction of Chaos Blast."
- Shadow the Hedgehog (Nintendo GameCube) United States instruction booklet, pg. 17.
- Sonic Team (December 15, 2005). Shadow the Hedgehog. PlayStation 2. Sega. Area: The Last Way. Japanese version.
- Excerpt from Sonic the Hedgehog: Official Strategy Guide
- 1UP. Archived from the original on 2 March 2016. Retrieved on 24 May 2020.
- Sonic Rivals 2 (PlayStation Portable) North America instructional manual, pg. 10.
- Sonic Team (14 November 2006). Sonic the Hedgehog (2006). Xbox 360. Sega. Area/Level: End of the World. "Shadow: Certainly, it might have been possible, if he was still alive."
- Sonic Central: Since Shadow is Sonic's enemy, what does this game mean for Sonic? Is he your main enemy in this game? How does Robotnik fit into things? / Sonic Team: Shadow is more of a nemesis to Sonic rather than a true enemy; they may be adversaries but there is a mutual respect between the two of them.
- “I'm Shadow. Shadow the Hedgehog. ...What? I look like Sonic? You have to be joking. Don't you ever put me in the same boat as that inferior half-wit!”, Mario & Sonic at the Rio 2016 Olympic Games
- Sonic Team (November 7, 2017). Sonic Forces. Nintendo Switch. Area/Level: Chemical Plant: Chemical Plant. "Shadow: Rouge, have you found the intel I was looking for? / Rouge: No, not yet. But I have reports that Eggman's database is located at the Chemical Plant. If we can check that out, we might find something there."
- Shadow the Hedgehog Last Story: I've heard enough! You're boring me to death, Black Doom! You're going down!
- Sonic Team (27 February 2004). Sonic Battle. Game Boy Advance. Sega. Area: Ending sequence (Emerl's Episode). "Shadow: This was Gerald's final program... Should a weapon go out of control, the weapon will terminate itself... ... ... ... It is my desire to bring hope to humanity. I can't stand it..."
- Sonic Team (7 November 2017). Sonic Forces. Nintendo Switch. Area/Level: World Map. "Infinite: Hahaha... Oh, this power, before we've even tuned it! Just as I thought, it is unrivaled! Not even Sonic will be able to stand against me now! / Shadow: Sonic? What are you plotting? / ... / Shadow: What--IS this? STOP! Where do you think you're going, Infinite?!"