Professor Gerald Robotnik (プãƒãƒ•ェッサー・ジェラルド・ãƒãƒœãƒˆãƒ‹ãƒƒã‚¯, PurofessÄ� Jerarudo Robotonikku?) is the grandfather of Maria Robotnik and Dr. Ivo "Eggman" Robotnik. Space Colony ARK, the Biolizard, Artificial Chaos, and various other projects. Fifty years before the main series, he attempts to create the "Ultimate Life Form" under the funding of the United Federation, hoping that it can help cure Maria's illness. He fails various times until meeting with the alien, Black Doom, and using his DNA to help his force. He learns of Black Doom's true plan (to destroy the planet), and prepares the ARK to act against Black Doom when the time comes. Gerald soon found the Gizoid, and took it to the Space Colony ARK for research. He managed to create a Link with the Gizoid, and figured out that it could learn how to do anything, and that it got stronger when absorbing Chaos Emeralds. He then started Project: Gizoid and equipped the robot with a "heart", a free-willed emotions-based AI. Unfortunately, the project was never finished as Gerald had to hand over the Gizoid. However, the Gizoid soon absorbed a large amount of weaponry, and devastated a large section of the ARK. After the accident, the government decided Gerald's experiments were dangerous to humanity, and sent the G.U.N. Agency to shut them down, killing Maria in the process. This caused Gerald to lose his grip on reality, and create plans to crash the ARK into the planet. He is then captured by the government and executed( he was shot in the chair he was chained in). His intentions to protect the Earth from Black Doom are revealed and he is respected as a hero. He is voiced by Chikao ÅŒtsuka in Japanese, Marc Biagi in the English version of Sonic Adventure 2, and Mike Pollock in Sonic X and Shadow the Hedgehog. -Wikipedia-
Vector the Crocodile is a large, strong crocodile. He is the "head honcho", and the brains, of the Chaotix Detective Agency. Divided between being "bossy" and "easy-going," his rough speech and outward appearance mask his clear reasoning and ability to resolve cases. For the right price he'll take on most jobs, unless they involve doing something immoral. Vector has a strong sense of justice and kindness, despite his argumentativeness. He often does unpaid work due to his charitable nature, leaving the agency constantly short on money. Vector hates having to work for the landlord, but he enjoys singing, and his trademark is a set of headphones. He is physically very strong and his powerful jaws are a formidable weapon. Vector was originally supposed to be in the sound test of the original Sonic the Hedgehog game, making him one of the oldest Sonic characters, alongside Sonic and Robotnik.
An innocent bystander that was caught up in some of the dealings of her father.
Froggy is a frog, and the best friend and buddy of Big the Cat. He has been rescued by Big and friends when he has gone missing or undergone a strange transformation.
Espio the Chameleon is an anthropomorphic chameleon who is an expert ninja. He is also 16 years old. He is described as the "guardian of honor" of the Chaotix, also being the calmest. He has a "militaristic discipline" while also 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. Espio also made an appearance in Mario and Sonic at the Olympic Games as a referee. GameZone staff writer Louis Bedigian claimed that "Espio must think he's part hedgehog because he can speed boost and become invisible".