Sonic the Hedgehog

Sonic the Hedgehog (ソニック・ザ・ヘッジホッグ) is Sega's mascot and the eponymous protagonist of the Sonic the Hedgehog series. He is an anthropomorphic hedgehog born with the ability to run faster than the speed of sound, hence his name, and possesses lightning fast reflexes to match. As his species implies, Sonic can also roll up into a concussive ball, primarily to attack enemies.

Ever since stepping into the battle against iniquity, Sonic has been the champion of peace and is renowned all over the world for saving it countless times. During his many adventures, Sonic has traveled from the ends of the world to the far reaches of space and time, facing countless trials that have tested him to the fullest, earning him many titles, allies and the scorns of several foes. Well-known for his legendary cocky attitude, easy-going demeanor and somewhat short temper, yet strong sense of justice, compassion, and love for freedom and adventure, Sonic uses his abilities to protect the innocent from his world and those beyond from the forces of evil, especially his arch-nemesis, Dr. Eggman.

Concept and creation
While several people have been involved in the creation of Sonic, the artist Naoto Ohshima, programmer Yuji Naka and designer Hirokazu Yasuhara are generally credited with the creation of the character.

In April 1990, Sega requested a game capable of selling more than 1,000,000 copies; a character who could compete against Nintendo's Super Mario, and a character to replace Alex Kidd as the company's mascot. Several character designs were submitted by its AM8 research and development department. These included an armadillo (who was later developed into Mighty the Armadillo), a dog, a Theodore Roosevelt look-alike in pajamas (who was later used as the basis of the design of the main antagonist Dr. Eggman) and a rabbit (who would use its extendable ears to collect objects, an idea that was later used for a separate Sega character named Ristar). Eventually, the mascot they selected was Naoto Ohshima's submission, a spiky teal hedgehog codenamed "Mr. Needlemouse," later renamed Sonic. Initial ideas for names for Sonic included "Raisupi" and "LS", truncation and plays on the word "light speed".

Sonic's color was based on the Sega logo, his shoe buckles based on Michael Jackson, his shoe color based on Santa Claus, and his personality was inspired by future-President Bill Clinton's "get it done" attitude, whom Ōhshima felt embodied a modern sensibility of wanting to get things done right away, righting wrongs as they presented themselves instead of letting them linger. According to Yuji Naka, Sonic's color also serves to symbolize peace, trust, and coolness (which are the attributes of Sonic's character). His trademark speed is based on Super Mario Bros. World 1-1, with Sonic creator Yuji Naka stating in issue 260 of Nintendo Power that "I always tried to get through the level as fast as I could," which inspired the initial concept for Sonic the Hedgehog. Sonic was created without the ability to swim because of a mistaken assumption by Yuji Naka that all hedgehogs could not do so.

A group of fifteen started working on Sonic the Hedgehog and renamed themselves Sonic Team. The game's soundtrack was composed by Masato Nakamura of the band Dreams Come True. Sega sponsored the group's "Wonder 3" tour, painting Sonic on the tour bus, distributing pamphlets advertising the game, and having footage of the game broadcast above stage prior to its release.

The original concepts gave Sonic fangs and put him in a band with a human girlfriend named Madonna. However, a team from Sega of America, led by Madeline Schroeder, "softened" the character up for an American audience by removing these elements. This sparked a heated issue with Sonic Team. Naka later admitted it was probably for the best. Sonic's precise age, weight, height and other physical characteristics vary depending on the continuity in which he appears and the style in which he is drawn. In the video games, Sonic's original design by Naoto Ohshima was with short spikes, a round body, and no visible irises. Artwork featuring this design and drawn by Akira Watanabe was displayed on the package artwork for Sonic the Hedgehog and most subsequent Sonic video games featured similar designs. When Sonic the Hedgehog 2 for the Mega Drive appeared, Sonic's proportions changed. The original 1:2 head to height ratio changed to 1:2.5.

Beginning with Sonic Adventure in 1998, Sonic was redesigned by Yuji Uekawa as a 15-year-old character, with longer legs and a less spherical body, longer and more drooping spikes, and emerald-green-colored eyes. Sonic was also purposefully made more of a “bad boy” for Sonic Adventure, so that his character did not become too cutesy like so many other character mascots (Yuji Naka stated that Hello Kitty already owned the market in cuteness). Further changes to the character's design were made in subsequent games, namely in Sonic the Hedgehog (2006) and Sonic Unleashed, adding visible fur, a more realistic design for a human world, and making him a bit lankier.

Appearance
Sonic is a thin anthropomorphic hedgehog with blue fur that covers most of his body, peach skin that covers his arms, muzzle and front torso, and emerald-green eyes. He has six long quills on the back of his head, two spines protruding from his back behind his shoulders, and a short tail.

For attire, Sonic wears two light-weight, hyper friction resistant red sneakers with white cuffs around the ankles, gray soles, and white straps across the top, the last of which are held down by a golden buckle on each foot. He also wears a pair of white gloves with sock-like cuffs on his hands.

Personality
Sonic is said to be "like the wind"; a drifter that is always on the move and is noted for being free-spirited and adventurous. He values freedom above all else and strives to live his life according to his own rules rather than the standards of those around him or for the sake of heroism and duty, never thinking twice about what other people say or think. Born to run, Sonic enjoys nothing more than traveling the world. Endowed with a strong passion for enjoying life, he is never in one place for long and always moves forward to look for his next challenge, making his life a never-ending series of adventures. Because of his need for freedom, Sonic loathes the idea of being constrained and being cooped up for too long makes him twitchy and restless.

Sonic's demeanor is always easygoing, cool, and carefree. However, he is often impatient, hates boredom, and at times possesses a short temper. Because of his impulsive nature, Sonic can be reckless and quick to act before thinking, throwing himself into trouble without a second thought and regards for others' warnings. Nevertheless, he is honest and always keeps his promises.

Sonic's personality is a juxtaposition of kindness and ferocity. He is extremely benevolent, driven by his own strong sense of justice and fair play and firmly stands for truth and freedom. However, he is never the one to rest in the face of injustice or oppression. He hates lies and evil in all its forms, exploding with anger when witnessing anything unjust and will do all he can to snuff it out, throwing his life on the line without hesitation. However, he usually sees his heroics as an opportunity to have fun, making him a thrill-seeker. To Sonic, saving the world is no big feat and just another thrilling episode in his life. When he finds himself in a pinch, he acts as though nothing can stop him. In times of crisis, though, he is aggressive and focuses intensely on the task at hand as if his personality has undergone an astonishing change. At the same time, Sonic has a big and kind heart and is fully committed to helping out anyone in need at any time, even if it means getting himself into trouble or being despised by others.

Sonic has a lot of self-confidence and possesses an enormous ego to match it, making him sassy, quick-witted, cocky, and at times overconfident. No matter the threat or how dangerous, Sonic always remains cool under pressure. In the original Japanese version, Sonic omits honorifics and speaks informally (if not rudely), using "ore" instead of "I" when addressing himself or others ("ore" is a boastful way to say "I" in Japanese). However, he sometimes uses honorifics when addressing close friends or acquaintances. Possessing a narcissistic tongue and big attitude, he often jokes around to light the mood and will also take any opportunity to taunt his opponents. Being so smug, Sonic has developed a habit of talking to mindless robots, even when he knows they cannot hear him. Despite this, he can be quite the gentleman when he wants to and be modest with fancy titles. Also, while Sonic generally assumes he can deal with things on his own, he also realizes he has friends to back him up in troubled situations and believes strongly in teamwork. Owing to his smugness and confidence, he often engages in playful banter with his enemies, such as his asking Infinite, as "optional" questions to glean into what the secret behind the latter's powers were, what the latter's favorite color was and whether he liked long romantic walks on the beach, as well as "asking" a Zavok replica if he would let Sonic join a party occurring on the Death Egg (referring to the commotion resulting from the Resistance's infiltration of the area).

Following his free-spirited nature, Sonic never dwells on the past or allows his painful experiences to weight him down. Instead, he lives in the present and always looks forward to his next adventure, holding no regrets for what has transpired. It is only in the moments of greatest loss that his macho and carefree appearance falls away. Sonic is also of incredibly strong character and will: No matter the situation, he never doubts himself or gives up, never once submitting to the darkness in his heart.

Sonic is extremely loyal to his friends and will risk his life for them without any due consideration. While he can leave them hanging, act rude towards them, or endanger them due to his fast-paced nature, Sonic never intends to make his friends unhappy and values them above all else, treating each of them as the most important person in his life. Equally, Sonic will always accept help from his friends and show great trust in them, though he is not above making mistrusting assumptions of them.

Regardless of the many foes he has faced, Sonic rarely considers them true enemies and instead tends to admire them for how powerful some of them are and how much fun they can give to him. Likewise, he is shown to have a remarkable capacity to forgive, forgiving Silver and working with him after he had tried to kill him twice.

Despite his outward demeanor, Sonic has shown to be much more insightful than he usually lets on, capable of seeing things others would have overlooked and give valuable and comforting advice that drastically changes the outlook of others, such as in the case of Elise, Merlina, and Blaze. This insight, combined with a charismatic personality, allows Sonic to get along with virtually anyone he meets, even if they were his enemies at one point.

Sonic has a fondness of the beauty of nature and he stands as a protector of it. He appreciates scenic views as seen in Sonic Colors and showed anger and rage when he found out that Eggman was polluting Planet Wisp's beautiful environment. In Sonic the Hedgehog (2006), Sonic is also shown to have a fondness for locations that are filled with flowers, trees, and other kinds of plants. Ironically, despite his inability to swim, Sonic also loves going to the ocean.

Sonic has been shown to enjoy music, but seems to have a special interest in rock music. Furthermore, it is displayed in Sonic Rush that Sonic also enjoys break dancing, which is reflected in his Trick Actions. His battle moves in Sonic Battle are also based on break dancing as mentioned in the attack descriptions. He also breakdances in numerous games, usually when he is victorious.

He also tends to get irritated when his foes often misidentify his species, namely by calling him a rat, making him correct them and state his actual species is a hedgehog. This was best demonstrated with his encounters with Erazor Djinn, and to a lesser extent with his encounter with Infinite at Mystic Jungle.

Powers and abilities
Despite not having undergone any known training, Sonic's years of battles have made him a skilled and powerful fighter. He has defeated giant robots, demons, and god-like beings on his own, gone up against and bested those with far more combat experience, and even beaten people who are his equal in abilities. It has also been noted that Sonic is steadily growing stronger; during the Time Eater incident, Sonic could beat the Egg Emperor/Perfect Chaos on his own where he previously required additional power. Sonic even told Infinite upon holding his own against the latter compared to the previous time they fought that he becomes more powerful every second. It is safe to say that Sonic is far more powerful than he lets on, but his overconfidence and reluctance to go all out usually keeps him from fighting at full strength. His victories over Emerl at the Gizoid's maximum potential and Perfect Chaos in his base form are prime examples of Sonic's true power. Regardless of his blocks, Sonic ranks amongst the most powerful characters in the series.

Sonic's greatest strength is his super speed, an innate talent that members of the hedgehog species possess. Sonic, however, has proven himself in a class of its own with his speed, having been credited as "the fastest thing alive" and even the fastest being in the universe. He has the ability to instantly accelerate to the speed of sound and run at speeds far greater than Mach 1, which is at the blistering speed of about 768 mph, and can run backward just as well as he can forwards. Due to such speed, he can scale vertical surfaces and ceilings, run over water, outspeed lasers, and even cause the ground to explode in his wake. Even then, Sonic can take his speed even further. By revving up in one place, he can take off at turbo speeds in an instant. He can also envelope himself in a blue energy field that lets him 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.

It is unknown what Sonic's unaided top speed is. In Sonic Battle, it is stated that he can move several times the speed of sound and when facing Ultimate Emerl, he went at least ten rounds with him in less than thirty seconds. It has often been stated that Sonic can move at supersonic speed (which ranges from 915-3,840 mph), and he has once been called the "the world's fastest, hypersonic hedgehog" (which ranges from 3,840-7,680 mph). There are as well records stating that Sonic can move faster than the speed of light, although their accuracy cannot be guaranteed. However, E-123 Omega himself calculated that Sonic's speed could potentially exceed light speed and Sonic has boasted that light speed is "small time" to him.

Sonic has demonstrated complete mastery of his speed in any environment and can use it for both high-speed offense and defense. 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, Sonic's is seemingly limitless as he is never winded from running. His speed also allows him to perform several impressive feats: he can heal himself by vibrating his body, launch shockwaves by spinning rapidly, leap in midair, launch stunning waves with fast kicks, increase the force of his blows by striking with increased momentum, and create barriers of super speed. He can also spin in circles or rotate his extremities at super speed to create winds strong enough to attack or blow away opponents, similar to aerokinesis.

Sonic possesses astounding kineticism, precision and has reaction time to match his speed. He has profound acrobatic skills and agility, along with enhanced reflexes that lets him avoid any incoming obstacles with precise and delicate movements. As seen in his first meeting with Silver, Sonic can even detect attacks beyond his field of vision due to his sharp reflexes. When launched into the air, he can also pull off several tricks before landing. He also has incredible jumping skills, capable of jumping up to several hundred meters even with extra weight.

Sonic possesses enhanced strength, though he has been noted to lack overall raw power by comparison. He can push and lift things several times bigger and heavier than himself, run with extra weight slowing down and his attacks can smash through metal and rock, and damage foes countless times his size. However, it is debatable whether the latter's power comes from his speed, strength, or a combination of both. Sonic's strength particularly lies in his legs; with a single kick, he can topple the Egg Golem, knock back several Egg Gunners at once and send Badniks flying. This does not mean that Sonic's arms are not strong either; he has enough strength to tear robots apart by hands and punch through a collapsed wall.

Sonic has several times demonstrated extreme resilience to damage. He can survive getting caught in the crossfire from all angles by Eggman's robots (which only knocked him out cold briefly), withstand the force of a massive explosion and a Hyper-go-on-based black hole unscathed, being pummeled with swords, and smash through several robots with his fist without discomfort, and take a ruthless pummeling from the Time Eater. Additionally, Sonic has more than once survived impacts from falls at extreme heights, bordering at the edge of space, only to shake it off when landing, and has even withstood atmospheric entry.

Sonic possesses an unbreakable and incorruptible spirit; in situations where most others would give up and where he is severely outnumbered and outgunned, Sonic never loses faith in himself and never surrenders. This trait enables him to keep on fighting when utterly exhausted or after taking an abnormal amount of damage. His will even lets him withstand mind-controlling powers, like the corruptive influence of Dark Gaia and the Overmind's psychic powers, though he did have some protection in the latter case. Even when possessed by the Ifrit, Sonic was arguably able to occasionally regain control.

Sonic has also demonstrated the ability to harness chaos energy for his own use; with a Chaos Emerald, Sonic can perform Chaos Powers, such as Chaos Control, and occasionally gain a boost in power.

Sonic's core offensive maneuver is the Spin Attack, a technique where he curls into a concussive ball or cutting disk and directs himself at his targets. With it, Sonic can shred or burrow through just about any substance given enough speed and hit with enough force to pierce colossal boulders. Highly adept in its usage, Sonic can utilize several variants of the Spin Attack for both ground- and aerial maneuvers, including the Spin Dash, Spin Jump, Homing Attack and the super-charged Focused Homing Attack.

Even without his Spin Attack, Sonic is a skilled hand-to-hand combatant. He mostly relies on his fast footwork since the majority of his power lies in his legs, though he has been known to use his fists and arms as well, albeit in a rather straightforward manner. His fighting style is mostly derived from breakdancing moves which utilize Sonic's legs to their fullest, allowing him wide-ranged and swift kicks. He has also been known to use flying forward kicks, split kicks, and scissor kicks. What Sonic lacks in strength for combat, he makes up for it in speed which he use to deliver lightning fast strikes in a short time. Sonic is also shown to excel in swordsmanship. Even as a rookie swordsman, Sonic could beat a dragon and after receiving formal training, he could best master swordsmen like the Knights of the Round Table. In addition to using advanced techniques, Sonic can apply his speed to his swordplay for quick and swift slashes, and become a buzzsaw by spinning with his sword, enabling him to slice clean through enemies.

Sonic has proven himself as a world-class Extreme Gear rider. He is said to move faster than he can run on an Extreme Gear and can go head-to-head with legendary Wind Masters like Jet the Hawk. Sonic seemingly has a knack for Extreme Gear riding, quickly grasping the controls on his first try and later developing advanced techniques despite being self-taught. After the second World Grand Prix, Sonic can be considered the best Extreme Gear rider in the world, having beat Metal Sonic in a race, who at that point was an "unbeatable" rider with the skills of the world's finest Extreme Gear riders at his disposal.

It appears that Sonic can control the strength and durability of his otherwise soft quills at will. While he is in spinball form, they appear to be extremely hard like buzzsaw blades; as demonstrated in Sonic Heroes, his quills (and body) are durable enough to slice through battleships without even moving at the speed of sound. In addition, Sonic's quills can sense nearby dangers, which they warn him about by creating a tingling sensation. Sonic has also demonstrated the ability to transfer his speed throughout various parts of his body, allowing him to immediately set off from stationary positions, and even channel it into objects to speed up their movements and make them pierce through solid objects as he does while running. He can also create an effect reminiscent of a time halt, even though it is unknown what it is derived from.

Equipment
Though he does not prefer to use weapons (mainly dissing firearms ), Sonic has wielded a number of tools during his adventures, albeit never permanently. During the Emerl incident, he utilized deployable landmines in battle, and one time, he would wield his own version of the Piko Piko Hammer. On his trip through the world of the Arabian Nights, Sonic also wore Shahra's Ring, allowing him to harness Shahra's magic for himself. Similarly, in the world of Camelot, Sonic would wield swords; he initially wielded Clarent, but later exchanged it for Caliburn, a sentient sacred sword with magical properties.

Super Sonic
By using all seven Chaos Emeralds, Sonic can enter a Super State, transforming him into Super Sonic. Easily his most frequent transformation, Super Sonic is Sonic's ultimate form. In this state, all of Sonic's abilities far surpass his normal ones. He is also able to fly and is nearly invulnerable. However, this transformation consumes a lot of energy, meaning it cannot be maintained for long.

Hyper Sonic
By using the power of the seven Super Emeralds, Sonic can achieve an extended and more powerful form of Super Sonic, called Hyper Sonic. This form basically shares the same traits as Super Sonic, except Hyper Sonic commands greater power and his Super State abilities are all upgraded.

Hyper Mode
A weaker variant of the super transformation. Sonic is capable of using this mode for a brief time on his own in Sonic the Fighters by drawing power from the Chaos Emeralds. In Hyper Mode, Sonic's speed and attack power greatly increase.

Darkspine Sonic
By harnessing the World Rings of rage, hatred, and sadness, Sonic can become Darkspine Sonic, a form powered by his emotions over Shahra's death. In this state, Sonic can fly, has greater strength, unlimited usage of his Soul Gauge powers and pyrokinetic abilities. Because of the intense emotions sealed inside the World Rings that Sonic uses to transform, however, he becomes slightly darker and more violent.

Excalibur Sonic
By using the power of the four sacred swords, Sonic is able to transform into Excalibur Sonic. This form grants Sonic a strong golden armor with a red cape, the ability to fly, greater strength and the power to wield the legendary sacred sword Excalibur.

Sonic the Werehog
After unwillingly absorbing the corruptive energies of Dark Gaia, Sonic gained the power to turn into a werewolf-like form named Sonic the Werehog at night time. In this state, Sonic loses his trademark speed, but he still retains his lightning reflexes and agility. He also gains super strength, sharp claws, extendable arms, and limited energy control. While Sonic's strong will prevents him from going bonkers like most others would, he does gain some minor feral behavior. He permanently lost this form before his battle with Dark Gaia when the energy from Dark Gaia that granted him his Werehog form was re-absorbed by Dark Gaia to complete its full awakening into Perfect Dark Gaia.

Color Powers
By harnessing different variants of Hyper-go-on from Wisps, Sonic can use specific Color Powers to transform into a certain form, such as a drill, a laser or even a fireball, each one possessing its own unique abilities. So far, Sonic has been able to transform into the Cyan Laser, Yellow Drill, Blue Cube, Green Hover, Pink Spikes, Purple Frenzy, Violet Void, Orange Rocket, Red Burst, Indigo Asteroid, Magenta Rhythm, Crimson Eagle, Ivory Lightning, Gray Quake and Black Bomb. However, these transformations require a steady supply of Hyper-go-on to be maintained.

Weaknesses
Sonic is incapable of swimming and sinks like a stone in water, which may be due to aquaphobia (Sonic believes that if he falls into water, he will be trapped with no one to get him out), though he does not demonstrate that fear very often. A notable exception is in Sonic Free Riders, where he is able to effortlessly swim underwater in the Dolphin Resort, and in Mario & Sonic at the Olympic Games and Mario & Sonic at the London 2012 Olympic Games, Sonic is the only character to wear a life-preserver. In some games, Sonic can bypass his weakness to water by running or sliding across its surface, leap out of the water with successive jumps, and survive extended periods of time underwater with Air Bubbles.

It has been stated that if Sonic does not sleep for eight hours during the night, it would spoil his running. In addition, he has trouble keeping his balance when coming to an sudden halt when running at high speed.

Relationships
During his adventures, Sonic has encountered many people and throughout it all, he has received many friends and foes alike. Sonic is well-known with his brotherly relationship with Tails, his friendly rivalry with Knuckles and his fierce arch-rivalry with Shadow. Sonic's arch-enemy is Dr. Eggman, but Sonic has come across even greater enemies throughout his adventures and escapades.

Dr. Eggman
Dr. Eggman is Sonic's eternal arch-enemy and nemesis, whom he has known longer than anyone else. Along with Tails, Eggman is one of the figures who has often shaped Sonic's destiny. Because of Sonic's hatred of anything unjust, he holds a great mutual loathing for the doctor and his evil plans to take over the world, and has spent years rescuing the victims of Eggman's conniving schemes. Whenever Eggman hatches a plan to conquer the world, Sonic always shows up and thwarts him. Because they always fight each other to win, Eggman has become a long time rival of Sonic's as well as an enemy. Also, whenever Sonic's anger explodes over injustice, he always makes Eggman the receiving end of this aggression.

Despite his dislike of Eggman, Sonic has never really taken account of his adversary and does not consider him his enemy in the true sense of the word. Whenever dealing with Eggman, Sonic remains fully confident that he can spoil his plans and never really takes them seriously. In fact, Sonic finds entertainment in spoiling Eggman's plans, seeing as a way of making his life an adventure, and is so used to beating him that he considers it an everyday job.

Usually, Sonic is rather frank or taunting towards Eggman and will almost always seize the opportunity to tease him with jokes and sarcasm. Sometimes, Sonic even finds Eggman more bothersome and annoying than threatening: when he discovered Eggman was behind the Time Eater in Sonic Generations, Sonic just facepalmed and shrugged disapproving. Nevertheless, he remains vigilant about Eggman and his actions, like when he alone refused to believe that Eggman had turned over a new leaf in Sonic Colors. In the cases Sonic does deem Eggman a legitimate threat though, he becomes very serious about the doctor and targets him with fierce anger.

When presented with a more terrible threat that endangers both of them and their goals, Sonic is willing to put aside his differences with Eggman and join forces with him to stop it. Even in such cases though, Sonic remains reluctant about it, feeling that teaming up with Eggman is like the end of the world and a dirty affair, and will in some cases suspect the doctor has an ulterior motive (which is often proven true). Because of Eggman's complicated tendency to instantly switch between morals, Sonic has a hard time figuring him out.

While Sonic has been know to make fun of Eggman by using his alias instead of his real name (which was possibly given by Sonic), he actually uses this name affectionately, rather than trying to make fun of him.

In spite of Eggman's horrible deeds, Sonic is content with just stopping the doctor and is never out to put him out of commission for good on purpose. Because of Eggman's tendency to survive their encounters and refusal to give up however, the doctor always returns with a new scheme, prompting Sonic to stop him again. As such, Sonic remains forever locked in a conflict with Eggman where it is nearly impossible for both individuals to defeat the other once and for all, making their battle a never ending one.

Miles "Tails" Prower
Miles "Tails" Prower is Sonic's best friend and sidekick, as well as his most faithful and loyal friend. Besides Eggman, Tails is one of the figures in Sonic's life who has often shaped his destiny. Sonic first met Tails on West Side Island where he noticed Tails following him. Though he was not interested in Tails at first, Sonic grew impressed with his tenacity when he kept up with him and let him tag along. When Dr. Robotnik then attacked West Side Island, Sonic joined Tails when the fox followed him into the conflict. In time, Tails proved himself a great ally to Sonic, and after defeating Robotnik, the two had built the foundation for the friendship that would define their future. Eventually, Sonic took Tails under his wing as his sidekick and took upon himself to train him. In time, the fox would become his protégé. Additionally, Sonic would stop bullies from teasing Tails for his twin-tails, which only improved Tails' admiration of him.

Since meeting each other, Sonic and Tails have been inseparable, their friendship having grown to the point where they have a brotherly relationship. In Sonic Advance 3, they are even noted to have an "Unbreakable Bond," and when Tails was once mind-controlled into fighting Sonic, Sonic never laid a finger on him in refusal to hurt his friend. Sonic himself sees Tails as a cute "adopted" kid brother and looks over him accordingly. Nevertheless, he respects and trusts Tails immensely and treats him as his equal partner in their adventures. Whenever on an adventure, Sonic always asks Tails to come along and will accept his help at any time. That said, however, Sonic will ignore Tails when he gives advice or information, often when it is most useful, though he is big enough to admit he should had listened to him.

Sonic cares very much for Tails' well-being. He will not hesitate to threaten those who endanger him, and will always make his safety his top priority, regardless of the matters on hand, like when he sent Tails away against his will when the Nega-Wisp Armor attacked them. When Tails finds himself in doubt, Sonic is always there to give him moral support. Throughout their adventures, the two have proven themselves a perfect team who can handle nearly anything; both provide strengths to the other's weaknesses (Sonic handles the muscle while Tails handles the smarts) and neither of them would get far without the other's aid. Tails as in particular proven himself Sonic's most reliable ally, always providing him with invaluable help, knowledge, and machines. In turn, Sonic is impressed with Tails' work and considers his technical skills unparalleled, though this faith makes him leave all the tech work to him.

Sonic usually holds absolute faith in Tails' skills, although that faith has been known to waver. When Sonic planned for Eggman to do the tech work to save the world from the Deadly Six's abuse of the Extractor, his own frustrations over having caused the mess made him doubt Tails' skills. This would strain their friendship over time. At the end though, Sonic apologized for doubting Tails, mending their brotherly bond.

Amy Rose
Amy Rose is one of Sonic's oldest and most loyal friends, and his self-proclaimed girlfriend. Since before meeting Sonic, Amy has looked up to him as her hero and been madly in love with him, and her greatest wish is to marry him. Sonic first met Amy during his adventures on Little Planet where he saved her from Metal Sonic and Dr. Robotnik's captivity which made them fast friends. Right from the start though, Sonic has not liked her like a girlfriend or reciprocate her advances. However, this attitude has done nothing to deter Amy.

Since their first meeting, Amy has chased Sonic down wherever he goes, with Sonic seemingly unable to escape her, and has tried to win his heart by any means. Sonic, however, is rather annoyed by her affection and even disturbed by her over-the-top displays, which makes him treat Amy as little more than an annoyance and deem her weird. As such, Sonic considers Amy a near constant pain in his life. Whenever Amy tries to show him affection, Sonic gets rather uncomfortable, exasperated or embarrassed and will try to avoid her when she goes overboard, usually by running away or by more rude means. Rejecting the idea of marrying Amy, Sonic would rather be locked up in a cell than marrying her (which is no small statement considering Sonic's loathing of being constrained) as seen in Sonic Adventure 2. Additionally, Sonic fears Amy's anger; he will become nervous or run away when he thinks he has provoked her, and Sonic often finds himself overwhelmed by her powerful personality. Over the course of the series, Sonic running away from Amy has become a running gag.

Regardless of how much dismay Amy has put Sonic through, she is considered one of his close friends. It is stated that in his heart he may not dislike her as much as it seems, and that deep down he might actually have some feelings for her. In Sonic Unleashed, Sonic was stumped that Amy did not recognize him as the Werehog, and when he shortly after saved her from some of Dark Gaia's Minions, he initially chose to run away than face her with his condition. Fortunately, learning that Sonic was inside the monster form, she claimed to him that he was still the Sonic she loves. Additionally in Sonic Lost World, Sonic was crestfallen when he thought Amy and the others had died from the Extractor.

Overall, Sonic cares about as Amy a good friend and worthy comrade whom he can rely on, and he appreciates her efforts to help him when she is not flirting with him. Also, whenever Amy is in trouble, Sonic will always be there to help her out should the need arise, though he tends to overlook her when she is caught in the middle of his showdowns with the villains.

Metal Sonic
Metal Sonic is Sonic's robotic alter ego, created by Dr. Eggman for the sole purpose of destroying him. He is one of Sonic's earliest foes and his first true rival, being able to copy both his speed and power. Both of them share a violent rivalry/enemy relationship with each other. Sonic first encountered Metal Sonic on Little Planet where the robot kidnapped Amy Rose, forcing Sonic to defeat him to save Amy, inadvertently turning Metal Sonic from one viewing him as an enemy into a bitter and deadly rival. On the other hand, Sonic has never considered Metal Sonic his enemy in the true sense of the word.

Since meeting each other, Sonic and Metal Sonic have almost always fought whenever they meet, never once having an instance where their objectives align. In Sonic's opinion, Metal Sonic is the worst creation Dr. Eggman has ever made due to how it always causes trouble for him, and he views Metal Sonic as a very serious threat. Regardless, Sonic always remains confident that he can beat Metal Sonic and considers him a "lame robot copy" which can never match up to the original that is him. Still, this does not keep him from enjoying testing his skills against him.

Over time, Sonic and Metal Sonic have had countless fights, with Sonic always managing to beat or tie with Metal Sonic in the end, though not without cutting it close on most occasions. However, these defeats have only increased Metal Sonic's hatred for Sonic and endowed him with an obsession to surpass and defeat him, promoting him to repeatedly challenge Sonic in vain. At one point, Metal Sonic's hatred and obsession for Sonic pushed him over the brink, making him usurp control of the Eggman Empire to build a robot kingdom with the goal of killing Sonic. He even adopted the warped belief that Sonic was his copy and that he was the real Sonic.

While Sonic has managed to defeat Metal Sonic time and time again, he rarely condemns Metal Sonic for his villainous actions in the aftermath. Instead, he gets a satisfaction from the challenge Metal Sonic provided him with and will promise his robot double that he will await their future rematches.

Knuckles the Echidna
Knuckles the Echidna is one of Sonic's greatest rivals and best friends. They have known each other for a long time, but their relationship is somewhat complicated, the two of them having been summed up once as "best frenemies." When Sonic first met Knuckles, they started off as enemies, with Knuckles trying to keep him from stopping the Death Egg's re-launch after being deceived. However, when the echidna discovered that Dr. Robotnik had tricked him, the two of them joined forces to keep Robotnik and his robots from stealing the Master Emerald, and they departed on good terms, befriending each other.

Sonic and Knuckles are much like oil and water. While Sonic exemplifies the wind and is laid-back, cool and free, Knuckles exemplifies the mountain and is stern, serious and unmovable, which cause them to argue a lot. Because of their differences and viewpoints of life, they do not understand each other or always see eye to eye. They share a competitive rivalry and often end up fighting when clashing, though their rivalry has become more friendly over time, being now more a play between the two. With Sonic's speed equaling Knuckles' strength in every way, their fights are always climactic.

Knuckles sees himself as Sonic's rival, though it has been implied several times it is because he envies Sonic's free lifestyle and self-reliant nature. Sonic meanwhile, always welcomes a challenge from Knuckles and enjoys teasing him for fun because of his serious nature, and will even try getting him angry so he can fight him.

A majority of their confrontations have been caused by Dr. Eggman, who would trick Knuckles into thinking Sonic (and to a minor extent, Tails) is the enemy; though, as time passed, Knuckles has stopped falling for Dr. Eggman's lies and is generally more aware of his plans. Whenever Sonic discovers Eggman has tricked Knuckles, he always chides him by calling him "Knuckle-head," which Knuckles does not take too well, though they always make peace with each other at the end of the day.

Despite their differences, Knuckles is Sonic's best friend next to Tails, having been described as such many times through the series, and being a vital part of Sonic's team. The two of them are connected by a hot-blooded friendship and according to Tails, they are "funny" together. While Sonic does not hold back on Knuckles' shortcomings, they deeply acknowledge each other and Sonic knows he can count on him to do what is needed to succeed. Over time, their relationship has improved greatly, though Sonic is still somewhat reluctant to admit when Knuckles is right and he was wrong. While Knuckles at times rebuts his help and claims he could do better, Sonic just rolls with it and is merely glad to help him. The two are also great and loyal teammates, having worked together multiple times, being called "Fighting Buddies" in Sonic Advance 3, and when they do so they form an unstoppable team. For better or worse, Sonic will also be there to give Knuckles needed, if not harsh, consoling whenever he is in doubt. Additionally, in Sonic Lost World, Sonic was crestfallen when he thought Knuckles and the others had died from the Extractor.

Shadow the Hedgehog
Shadow the Hedgehog is Sonic's arch-rival. They look almost identical (to the extent that many initially got them confused), and they can match each other in speed, agility and abilities, including Chaos Control. The two of them first met each other as enemies, with Sonic holding a grudge at Shadow for getting him into trouble with GUN, but they put aside their differences to team up and save the world from Gerald Robotnik's doomsday plans. Since then, they have been both lethal adversaries and comrades. In addition, immediately before their final fight, Sonic, when explaining how he survived Eggman's earlier death trap against him, credited Shadow for "saving him" (referring to Shadow's frequent use of Chaos Control inspiring Sonic to do the same via a Fake Emerald), and also freely answered Shadow's question of who he was as "just a guy who loves adventure."

Shadow is the antithesis to all that Sonic stands for, and ever since they first met they have fought, argued, and even had outright death matches, though Sonic is never out to take Shadow's life and does not consider him an enemy in the true sense of the word. Their moral differences are as far apart as black and white, always causing the two of them to clash. Sonic has a joyful, free-spirited attitude that looks for fun adventures, while Shadow is a brooding loner with a merciless and excessively violent edge. Sonic has few limitations on his goals and will do anything to help save the world, but Shadow will stop at nothing to get what he wants without any concern for who or what it affects. Nevertheless, they do not care of each other's views and they always see their conflicting differences as yet another reason to fight each other.

Both Sonic and Shadow shared a bitter arch-rivalry. When they first met, Sonic accused Shadow of copying him, with Shadow maintaining a mutual belief regarding Sonic. This feeling is still present in both of them because each believes he is better than the other. Regardless, their rivalry has developed over time and is now more friendly, yet still fiercely intense.

Out of all his rivals, Shadow is the one whom Sonic struggles most with. As shown in all their clashes, they are each other's equal, with both sides neither lacking in any category that separates them from skill in their respective prowess: while Sonic is becoming faster and more honed than Shadow, Shadow is becoming stronger and more destructive than Sonic, which has only increased the intensity of their rivalry. They have an unshakable need to showcase their growth and improvement for every encounter they have, and anything considered competitive is suitable for their arch-rivalry, though Sonic usually remains more casual about it than Shadow and enjoys testing his skills against him.

Despite their differences, Sonic and Shadow share a mutual respect for each other, though this is rarely apparent because they always argue and fight. Sonic himself has acknowledged Shadow's capabilities, even admitting that Shadow is only one who would have a chance against him in a race, and after Shadow sacrificed himself to save the world in Sonic Adventure 2, he recognized him as a brave and heroic hedgehog. Sonic also appears to hold faith in Shadow's sense of right and wrong to a certain extent as seen in some of the scenarios of Shadow the Hedgehog where he would show disbelief and confusion about Shadow siding with the Black Arms, even admitting in one scenario that he did not believe Shadow had it in him for his selfish acts.

Regardless of their disagreements, they are willing to put their differences aside for the greater good, and together they are an unbeatable team. Overall, there is always extreme tension between Sonic and Shadow, but they have matured over time, with Shadow having more faith in Sonic's capabilities and Sonic becoming more tolerant of Shadow's violent tendencies.

Cream the Rabbit
Cream the Rabbit is basically like a younger sister to Sonic. Cream similarly looks up to Sonic like an older brother. Cream also takes him as her savior and respects him a lot. She often calls him by the name of "Mr. Sonic" due to her education in manners.

The two of them first encountered each other when Sonic saved Cream from Dr. Eggman, which led to a smooth relationship between the two. When they met, Sonic was surprised at how polite Cream was.

In Sonic Rush, Cream marks Sonic as the first person to seek help from for Blaze. This shows the high caliber of respect Cream has for Sonic. She was also the one who made the ties between Blaze and Sonic closer.

Blaze the Cat
Blaze the Cat is one of Sonic's friends and most valuable allies. He first met Blaze in Sonic Rush where he initially suspected she was involved with Dr. Eggman Nega's scheme. Once he learned Blaze was working on saving the world, albeit alone, Sonic insisted to help her only to be rejected. Sonic still followed Blaze, but his insistence to aid her only made Blaze fight him to make him leave. Even while battling however, Sonic tried to reason with Blaze, who berated him with the full fury of her emotions. Afterwards, Sonic came to understand Blaze's past and he told her to be true to herself. His advice helped Blaze realize that accepting help would benefit her, and they became friends. Sonic soon after established a firm belief in Blaze, which helped restore her confidence when the Sol Emeralds lost their power and led to her first transformation into Burning Blaze. After threat had passed and they returned home, they thanked each other and promised to meet again.

Since then, Sonic and Blaze have steadily become better friends and allies. They have a developed a custom where they shake hands as they depart, signifying their growing friendship and respect, and the promise to meet once more. Sonic and Blaze are alike in many ways, having similar skills and duties, yet very different backstories and contrasting personalities: Sonic being inwardly free and adventurous, yet outwardly level-headed and cool, whereas Blaze is outwardly stoic and blunt, yet inwardly highly emotional. However, their differences does little to hurt their relationship and is later shown to mix very well as their friendship and mutual understanding grows. They are also shown to be great partners in combat, working in sync.

Sonic and Blaze share a great deal of mutual respect and trust. Like Blaze respects Sonic and his skills, Sonic acknowledged Blaze's, especially since she is one of the few who has tied with him in combat. Even shortly after befriending her, Sonic entrusted her to save Cream, while Blaze trusted him to face Eggman Nega. Also, whenever Blaze's emotions get the better of her, Sonic will be there to remind her of what is important. Additionally, Sonic is responsible for many changes in Blaze's outlook on life; their time together has enabled Blaze to discover the meaning of friendship which ultimately let her use the Sol Emeralds, and his advices got Blaze to see her pyrokinetic powers as a gift than a curse.

Silver the Hedgehog
Sonic and Silver the Hedgehog first met during the events of Sonic the Hedgehog (2006). The two were enemies at first because Silver had traveled though time and was intending to kill Sonic believing that he was responsible for destroying the world by releasing Iblis onto it and was bent on saving the future. But Silver befriended Sonic when he discovered, with Shadow's help, that Sonic was not the Iblis trigger and that Mephiles the Dark had lied to him. The two worked together to save Princess Elise and when Sonic was killed by Mephiles, Silver realized that they could save Sonic with the power of the Chaos Emeralds. Afterwards Silver teamed up with Sonic and Shadow to defeat Solaris. But since the events of the game were erased from history, Sonic and Silver never met. In their new meeting in Sonic Rivals, Silver had traveled to the past to bring Eggman Nega back to the future, but he seems to be more competitive to Sonic as they raced each other see who would get to Eggman Nega first but later they teamed up with each other at the end to defeat Eggman Nega and also in Sonic Rivals 2 to defeat the Ifrit.

Silver seems to have a bit of a disliking towards Sonic mostly because he thinks that he is cheeky and foolish, much the same how Shadow thinks of Sonic at times. Silver's haughty attitude tends to annoy Sonic at times as well as seen in Sonic Rivals when he says, "Yo Silver, you're starting to get on my nerves". But they will work together and lay aside their differences whenever the time is right. An example is in Sonic Colors after Silver challenges Sonic to a mission, he asks if he needs any help. In Sonic Generations, Silver is the only rival who wants a friendly fight. He also appeared at the Center of Time after Sonic was knocked out by the Time Eater, Silver says to Sonic: "I know you can do this Sonic!". They are even more friendlier in Sonic Forces, where they work together to reclaim the world from Eggman's reign

Chip
Chip (also known as Light Gaia) is a dear and good friend to Sonic. When Chip first saw Sonic, he was afraid of his Werehog form, but he soon realized he was a good guy. When Sonic then told Chip that he would help him recover his memories, Chip quickly took a liking to Sonic and thanked him wholeheartedly. In addition, Chip subconsciously felt kindness in Sonic and wanted him to help him.

Chip spent most of his time next to Sonic, and soon formed a great friendship with him. Chip also enjoyed participating in friendly competitions with Sonic, like when they fought for the last dumpling in Chun-nan. However, Chip was sometimes a nuisance to Sonic due to his naive frankness would occasionally annoy him, although he never had a bad intention. Also, when he accidentally caused Sonic to become depressed with his Werehog form, Chip tried to cheer him up.

After recovering his memories, Chip was deeply grateful to Sonic for everything he had done for him. However, he did not want Sonic to get involved in his conflict with Dark Gaia and he tried to leave. However, Sonic persuaded him to help him anyway, and Chip thanked him. During his battle with Dark Gaia, Chip prioritized Sonic's well-being whenever he was weak, such as when he was weakened by the loss of Dark Gaia energy or when he fell unconscious after defeating Perfect Dark Gaia. When the last continent fell and they had to leave, Chip gave him a goodbye before returning him to the surface. There, Chip contacted Sonic telepathically, telling him that he would never forget him and that he would always be with him.

Jet the Hawk
Sonic has been rivals with Jet the Hawk since they first met, and their dynamic relationship is based on their competitive nature and distinct respect for one another. In their first meeting, Sonic lost to Jet in an Extreme Gear chase, but rather than being upset, Sonic eagerly recognized him as a worthy new rival.

Early on, Sonic's rivalry with Jet was rather one-sided, and Jet would often anger Sonic with his constant mockery of him. Nevertheless, Sonic recognized Jet's skills as an Extreme Gear rider and kept a professional, yet competitive, attitude around him. Eventually, Sonic settled his own dispute with Jet after he beat him in a race. Soon after, they would establish a more friendly relationship based on mutual respect, and promised each other to compete again later, though they still remain firm rivals.

Since defeating Jet, Sonic has kept a more relaxed and tolerant attitude towards Jet, taking his insults and rash determination to beat him in stride. Nevertheless, their rivalry remains as strong as ever, and Sonic will gladly, if given the right opportunity, race him for fun. However, even when determined to beat Jet, Sonic does not wish to have any unfair advantages, and will give Jet the chance to race him at his best. Despite how many times they face each other, their rivalry has seemingly no end in sight, although Sonic always looks forward to his next rematch with Jet.

The Deadly Six
The Deadly Six are some of the worst enemies Sonic has ever faced. Unlike his past foes whom he has never viewed as actual enemies, the Deadly Six are the only ones Sonic has shown true contempt for.

Sonic first met the Deadly Six while they were under Eggman's control, where he treated them with confident mockery like any foe. However, when Sonic recklessly got rid of the Cacophonic Conch used to control the Deadly Six, they rebelled and planned to destroy the world, making Sonic responsible for the subsequent danger to the planet. As such, Sonic set out to stop them with more seriousness. He soon grew extremely hostile towards them when they captured Tails, an act of which made Sonic lose his cool for once. As he sought to save Tails, Sonic threatened the Deadly Six with aggressiveness and spite which only intensified as Zavok taunted him with his plans to roboticize Tails and his friends' apparent deaths. By the time of their final showdown, Sonic was thoroughly tired of them and threatened them aggressively when he thought they had turned Tails into a robot. In the end though, Sonic defeated the Deadly Six and got Tails back, redeeming himself and proving himself the hero he is.

When encountering Zavok again (or rather, his replica) aboard the Death Egg, his demeanor towards him was more laid back, as evidenced by Sonic engaging in his usual confident mockery towards Zavok both prior to and immediately after the fight.

Infinite
Sonic first encountered Infinite in the City, where he was beaten easily by the mysterious henchman of Dr. Eggman. Later, when encountering Infinite at Mystic Jungle and had his first formal meeting with Infinite, Sonic dismissed the latter's insinuation that his sweat was due to fear and explained he ran all the way to the location to save Silver, and also proceeded to smugly explain to Infinite that the latter failed to leave an impression on him at all despite the earlier beating, not even knowing his name. Upon learning it, however, Sonic, in his trademark banter, then tried to get Infinite to reveal the secret to his power, although Infinite refused to divulge the ability. He also expressed some annoyance at the latter's reference to him as a "sewer rat." Although he managed to do much better against the enigmatic warrior than before, he still ultimately lost the battle due to Infinite's powers. Ultimately, he alongside the Avatar managed to defeat Infinite for good at Eggman Empire Fortress, with him also telling Infinite that the reason he lost was because he and his replicas lacked heart, soul, and the bonds of friendship.

Avatar
Sonic met the Avatar after the former escaped from the Death Egg and latter having arrived with a shuttle to rescue him. Together they proceeded to team up on various missions. He ultimately inspired the Avatar to not give in to his fear against Infinite. Likewise, the Avatar was shown to be loyal to Sonic, making an attempt at saving him from the Null Space, and ultimately succeeding, despite being sucked in with him. After the war was over, Sonic suggested they would see them around when the Avatar went their own way and took their leave from the Resistance after it was disbanded.

Friends/allies

 * Miles "Tails" Prower (best friend and sidekick, close as brothers)
 * Knuckles the Echidna (best friend and rival)
 * Amy Rose (good friend)
 * Big the Cat
 * Cream the Rabbit
 * Shadow the Hedgehog (ally and arch-rival)
 * Rouge the Bat
 * E-123 Omega
 * Vector the Crocodile
 * Espio the Chameleon
 * Charmy Bee
 * Mighty the Armadillo
 * Ray the Flying Squirrel
 * Bean the Dynamite
 * Bark the Polar Bear
 * Tikal
 * Lumina Flowlight
 * Blaze the Cat (close friend, partner in combat)
 * Coconut Crew
 * Marine the Raccoon
 * Silver the Hedgehog (friendly rival)
 * Emerl
 * Vanilla the Rabbit
 * G.U.N.
 * The Commander
 * Princess Elise
 * Shahra
 * Caliburn
 * Merlina
 * Shade the Echidna
 * Professor Pickle
 * Chip (good friend)
 * Wisps
 * Yacker
 * Classic Sonic
 * Classic Tails
 * Avatar (partner)

Rivals

 * Shadow the Hedgehog (arch-rival, occasionally friendly)
 * Knuckles the Echidna (friendly rival)
 * Silver the Hedgehog
 * Jet the Hawk (in speed)
 * Metal Sonic
 * Johnny

Enemies

 * Eggman Empire
 * Dr. Eggman (arch-enemy)
 * Orbot
 * Cubot
 * Metal Sonic (robotic doppelgänger and second arch-enemy)
 * Fang the Sniper
 * Chaos (formerly)
 * Void (formerly)
 * Biolizard
 * G.U.N (formerly)
 * Dr. Eggman Nega
 * Captain Whisker
 * Johnny
 * Mini & Mum
 * Black Arms
 * Black Doom
 * Iblis
 * Solaris
 * Ifrit
 * Erazor Djinn
 * Nocturnus Clan
 * Imperator Ix
 * Dark Gaia
 * King Arthur
 * Classic Eggman
 * The Time Eater
 * The Deadly Six
 * Infinite