Sonic the Hedgehog is a blue anthropomorphic hedgehog and the main protagonist of the series. Developed as a replacement for their existing Alex Kidd mascot, as well as Sega's response to Mario, his first appearance was in the arcade game Rad Mobile as a cameo, before making his official debut in Sonic the Hedgehog (1991). Sonic's greatest ability is his running speed, and he is known as the world's fastest hedgehog. Using the power of the seven Chaos Emeralds, he becomes Super Sonic and can achieve even greater speeds.
Doctor Ivo Robotnik, better known by his alias Doctor Eggman, is a human mad scientist and the main antagonist of the series. Debuting in the first game of the series, Sonic the Hedgehog, he was shown attempting to collect the Chaos Emeralds and turn all of the animals inhabiting the land into robots. He is a self-proclaimed or certifiable genius with an IQ of 300. His fondness for mechas has made him a renowned authority on robotics. Ultimately, Eggman's goal is to conquer the world and create his ultimate utopia, Eggmanland, alternatively known as the Eggman Empire and Robotnikland.
Miles Prower, better known by his nickname, Tails, is a two-tailed fox who is Sonic's best friend and sidekick. His name is a pun on "miles per hour". He can use his tails to propel himself into the air like a helicopter for a limited time. Yasushi Yamaguchi, originally the main artist and zone designer for Sega's Sonic Team, designed Tails for an internal competition for a sidekick to Sonic. His first appearance was in Sonic 2 for the Game Gear, where he was kidnapped by Doctor Robotnik for a "hefty" ransom. He was first made playable in the Genesis version of Sonic the Hedgehog 2. Tails has appeared in almost every Sonic game since his first appearance. Tails starred in two solo spin-off games for the Sega Game Gear in 1995 Tails' Skypatrol, and Tails Adventure. Frequently portrayed as a sweet-natured and humble fox, Tails used to be picked on because of his twin tails, before he met Sonic. Tails is very clever and has excellent mechanical skills.
Amy Rose is a pink hedgehog and Sonic's self-proclaimed girlfriend, who is an energetic tomboy. Amy was created by Kazuyuki Hoshino for Sonic the Hedgehog CD (1993), although she appeared in Kenji Terada's Sonic the Hedgehog manga a year before. Hoshino created her in-game graphics, with many staff members contributing ideas to her design. Her headband and trainer shoes reflected Sonic CD director Naoto Ohshima's tastes, and her mannerisms reflected the traits Hoshino looked for in women at the time. Her fur color was red at first, and her skirt orange. The character had two other names in game previews: Rosy the Rascal and Princess Sally (a character in the Sonic the Hedgehog TV series and comics). Amy received her present design, with a red dress and knee-high leather boots, in Sonic Adventure (1998), courtesy of designer Yuji Uekawa.
Metal Sonic is an evil robotic version of Sonic created by Dr. Robotnik. He possesses great strength, including a laser cannon, a jet engine and a force field device he can use to protect himself from projectiles and certain attacks. He usually only communicates with a series of electronic noises.
Knuckles the Echidna is a red echidna and one of Sonic's friendly rivals. First introduced in the Genesis game Sonic the Hedgehog 3, Knuckles lives on Angel Island, which hovers in the sky due to the power of the Master Emerald. As the last surviving member of the Echidna people who once inhabited the island, his duty is to guard the Master Emerald.
Vector the Crocodile is a large crocodile who is the "head honcho" and brains of the Chaotix Detective Agency. Divided between being both "bossy" and "easy-going", his rough speech and outward appearance mask his clear reasoning and high competence in solving cases. For the right price he will take on most jobs, unless they involve doing something immoral. Vector has a strong sense of justice and kindness, despite his argumentative nature. He often does unpaid work due to his charitable nature, such as finding a lost child or taking up meager chases for children, leaving the agency constantly short on money. Vector hates having to work for the landlord, but he enjoys singing, and his trademark accessory is a set of headphones. He is physically formidable to the point of being comparable to Knuckles, with his powerful jaws being his most reliable weapon.
Espio the Chameleon is a chameleon who is a ninja warrior. He is described as the "opinionated number one" of the Chaotix, also being the calmest. He has a "militaristic discipline" while being quiet and laid back. Confident in his skills, opinionated and self-obsessed, he revels in training and self-discipline. He is not concerned by danger, and often yearns to face it in order to use his ninja skills. With his extensive training in ninjutsu and an ability to turn himself invisible, he is able to move around unnoticed. However, a blunder like a sneeze could cause him to inadvertently become visible.
Charmy Bee is a bee who is the "scatter-brained funny-kid" of the Chaotix. He is cheerful, curious, playful, careless, and greatly energetic, often talking about things no one else cares about. Charmy's childish tomfoolery makes the rest of the detective agency staff look professional, and he is seen by others as a "cute mascot". Despite an innocent, good-natured and light-hearted personality, he uses his stinger on rare occasions where he gets angry. In addition to being a playable character in Sonic Heroes and Shadow the Hedgehog, he made cameos in all the Mario & Sonic at the Olympic Games installments as a referee.
Big the Cat first appeared in the 1999 Dreamcast game Sonic Adventure, where he was placed to justify the presence of a fishing rod in the game, although he was conceived beforehand. Big is a large, purple anthropomorphic cat, who is depicted as—while unintelligent—sweet, easygoing, and physically strong.
Shadow the Hedgehog is a character created by the Japanese game developers Takashi Iizuka, Shiro Maekawa, and Kazuyuki Hoshino. He is a major character in Sega's Sonic the Hedgehog franchise. Shadow is an anthropomorphic black hedgehog created by Professor Gerald Robotnik, the grandfather of Doctor Eggman. Shadow shares design traits and attributes with Sonic the Hedgehog. He is an antihero who has good intentions but will do whatever it takes to accomplish his goals, putting him at odds with Sonic.
Professor Gerald Robotnik is the paternal grandfather of Maria Robotnik and Dr. Ivo "Eggman" Robotnik, originally introduced in Sonic Adventure 2. Fifty years before the main series, he constructed the Space Colony ARK and researched immortality for the United Federation in an attempt to create the "Ultimate Life Form", hoping that it could help cure Maria's illness, leading to the creation of Shadow the Hedgehog. However, the failure of an earlier prototype led the United Federation to shut down the project and cover up its existence, with the military organization GUN leading a violent raid on the ARK during which Maria was killed. Fueled by anger over his granddaughter's death and becoming resentful of humanity's increasingly callous nature, Gerald converted the ARK into a doomsday weapon and brainwashed Shadow before being executed, hoping the hedgehog would destroy the world in retribution. The stories of Sonic Battle, Shadow the Hedgehog and Shadow Generations have further expanded on the character's backstory and motivations, including his discovery of the Gizoid and his collaboration with the Black Arms aliens to create Shadow.
Maria Robotnik is a character that appears mostly in flashbacks in Sonic Adventure 2 and Shadow the Hedgehog. She is the granddaughter of Professor Gerald Robotnik, and is the cousin of Dr. Ivo "Eggman" Robotnik. Maria suffers from the terminal illness known as "NIDS" (Neuro-Immuno Deficiency Syndrome), which was incurable at the time. Gerald takes on Project Shadow in order to save her life. Soon after Shadow is created, the two form a familial bond, though it is short-lived as the government organization "GUN" soon raids the ARK, fatally shooting Maria. Before she dies, she encases Shadow in an escape pod and asks him to believe in humanity. This experience with Maria scars Shadow for life and initially leads him to attempt to destroy the world, but ultimately his determination to keep his promise to her leads him to team up with Sonic and save the earth multiple times. The relationship between Maria and Shadow is further explored in Shadow Generations and its associated prequel shorts. In the game's story, Shadow is reunited with Maria after she and Gerald are pulled from the past by the Time Eater, and she helps him overcome Black Doom's influence. Though he is tempted to warn them of their fates before they go back, Maria encourages him to move on and continue to protect humanity.
Cream the Rabbit is a peach-colored rabbit with a constant companion named Cheese, a blue Chao with a red bow-tie. Their names are based on "cream cheese". Cream is portrayed as being naive because of being brought up like a princess by her mother, Vanilla. She always politely minds her manners but sometimes acts childishly. Cream can achieve flight for short periods of time by flapping her two large ears, while Cheese often attacks on Cream's behalf by ramming into her adversaries.
Blaze the Cat is a purple cat princess from an alternate dimension. She has been appointed as guardian of the Sol Emeralds, her dimension's version of the Chaos Emeralds, making her role similar to that of Knuckles the Echidna. She is portrayed as calm and levelheaded, hiding her true feelings. She is sometimes "bogged down" by her own strict discipline and devotion to her position, making her appear withdrawn. Blaze can control fire, but wears a cape to conceal it as she was teased about her pyrokinetic abilities when she was young. Using the Sol Emeralds, she transforms into Burning Blaze. Blaze wears a purple dress and white tights with pink high heels and a yellow necklace.
Black Doom is the leader of the Black Arms, an invading alien force that seeks to conquer the Earth and harvest the human species as a source of energy. His first appearance is in Shadow the Hedgehog as the main antagonist, where it is revealed that Shadow was created from his blood by Gerald Robotnik. He attempts to control Shadow using their blood connection, but Shadow resists this and ultimately defeats him.
Silver the Hedgehog is a silver-furred hedgehog from 200 years in the future of the main timeline. He first appeared in the 2006 Sonic the Hedgehog. His individual episode revolves around him traveling back in time with Blaze the Cat to find and slay Sonic the Hedgehog, who they were tricked into believing is the cause of their world being destroyed in the future. Silver's primary ability is telekinesis; he is able to levitate objects and use them as projectiles to either defeat enemies or interact with his environment. Like Sonic and Shadow, he transforms into his "super form" by using the power of the seven Chaos Emeralds.
Orbot is a red robotic assistant of Dr. Eggman. He generally assists in monitoring Eggman's data and facilitating his schemes, though he can be lazy and often makes sarcastic remarks pointing out general flaws in Eggman's plans. While an earlier version of the character appears in Sonic Unleashed under the name "SA-55" (a play on the word "sass") he appears with his finalized name and design beginning in Sonic Colors, alongside a similar yellow robot named Cubot Conversely to the intelligent Orbot, Cubot is rather slow, not witty, and frequently makes mistakes. He suffers from a defect in Sonic Colors that causes him to randomly speak with different accents. The two have continued to appear as assistants to Dr. Eggman in subsequent titles, such as Sonic Generations, Sonic Lost World and Sonic Forces. The duo made a cameo in Mario & Sonic at the London 2012 Olympic Games as one of the helping characters in the London Party, copying stickers for the participants. The duo appeared in Mario & Sonic at the Sochi 2014 Olympic Winter Games as the hosts of the Action and Answer Tour and in the Sonic Boom animated series.
Sage is an artificial intelligence created by Doctor Eggman that resembles a young white haired girl. She was introduced in Sonic Frontiers, in which Eggman attempts to use her to investigate the ruins of the Ancients, an alien race that brought the Chaos Emeralds to Earth. Upon learning the portal could release the End, a malevolent entity sealed by the Ancients, Sage traps Eggman in Cyber Space for his protection. As the End manipulates Sonic into aiding in its release, Sage opposes him with the Ancients' robotic weapons. Though she treats Sonic coldly at first due to her programming by Eggman, she gradually develops a respect for him. Similarly, as he spends more time with Sage, Eggman begins to see her as more than an artificial being, coming to regard her as his daughter. In the game's default ending, Sage sacrifices herself to help Sonic defeat the End, but is revived by Eggman using the Ancients' technology; in the "Final Horizon" update, she survives altogether.
