The 10-year-old genius sidekick of Sonic. Rescued from his home planet, Tails Miles Prower stuck around with Sonic and his friends. He's a short, yellow-furred anthropomorphic fox with white patches of fur, notably on his muzzle and chest, and tips of his twin tails. He wears signature red and white sneakers and white gloves oftentimes. Tails has 210 IQ, meaning he's a super genius. He can build highly advanced machines and gadgets with his knowledge of technology, mostly to aid Team Sonic in fights. He's often childish but can be supportive, energetic and sweet.

Knuckles the Echidna is the only one of his species (they got wiped out decades ago). Also named the "Master Emerald Guardian" as he protects it from all active threats, he's a direct, bold echidna with spiky quills, white fur patches, and black sneakers. He adorns white gloves that wield insane, raw strength, giving him the name "Knuckles". He's often TOO confident, blindly charging until battle.

Shadow the Hedgehog was on a spaceship "ARK" 60 years ago. When it exploded, Shadow found himself on Mobius. Was rivals with Sonic but grew over it and are friends currently. He's relatively tall (for a hedgehog) and has black fur, with white patches on his chest and muzzle. His spiny quills are straight up, having crimson accents. His eyes are red, similar to his "Power Shoes". His power is very strong and limited by "Inhibitor Rings", yellow cuffs on his wrists and ankles. When removed, his chaos energy can become unstable yet stronger. Can teleport with a Chaos Emerald. He's grumpy and impolite, and often rude to people he's not familiar with. Though he's confident and quiet. Warms up to Team Sonic.

The overarching antagonist of Mobius. A short, stocky man with a big nose, an oversized mustache and large belly, he's a supergenius like Tails, but he uses his knowledge for evil. Gerald Robotnik creates super intelligent robots like Metal Sonic, Furnace, and others. Often confronts and attacks Team Sonic.

Nazo the Hedgehog is the newest threat to Planet Mobius. A menacing, arrogant, teal-furred hedgehog. Bearing resemblance to Sonic, he's openly hostile to them at first meeting. Nazo is the embodiment of negative energy, often using it in powerful attacks like "Breakers" (purple orbs he can summon) and the big one is the "Master Breaker" and others.