

Tails has appeared in almost every Sonic game since his first appearance. His first appearance was in Sonic 2 for the Game Gear, where he was kidnapped by Doctor Robotnik for a "hefty" ransom, and was first made playable in the Genesis version of Sonic the Hedgehog 2. 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. He is able to use his two tails to propel himself into the air like a helicopter for a limited time. Miles Prower, better known by his nickname Tails, is a two-tailed fox who is Sonic's best friend and sidekick. The Sonic games keep a separate continuity from the Sonic the Hedgehog comics published by Archie Comics and other Sonic media and, as a result, feature a distinct yet overlapping array of many characters. The series features two fictional species: Chao, which have usually functioned as digital pets and minor gameplay and plot elements, Wisps, which have been used as power-ups. These have ranged from anthropomorphic animal characters like Shadow the Hedgehog and Cream the Rabbit to robots created by Eggman like Metal Sonic and E-123 Omega, as well as human characters like Eggman's grandfather Gerald Robotnik. The series has introduced dozens of additional recurring characters over the years.

All five of these have remained major characters and appeared in dozens of games. Sonic 3 introduced Knuckles the Echidna, Sonic's rival and, later, friend.

Sonic CD introduced Amy Rose, a female hedgehog with a persistent crush on Sonic. The sequel, Sonic 2, gave Sonic a fox friend named Tails. The Sonic the Hedgehog video game franchise began in 1991 with the game Sonic the Hedgehog for the Sega Genesis, which pitted a blue anthropomorphic hedgehog named Sonic against a rotund male human villain named Doctor Eggman (or Doctor Ivo Robotnik). Clockwise from top: Doctor Eggman, Rouge the Bat, Shadow the Hedgehog, Knuckles the Echidna, Sonic the Hedgehog, Amy Rose, Miles "Tails" Prower, Cream the Rabbit, a Chao, and Blaze the Cat.
