Tails

Miles Prower, who is better known by the nickname of Tails, is a flying, two-tailed yellow fox from the Sonic the Hedgehog series. He is a sidekick to Sonic similar to how Luigi is a sidekick to Mario. Tails has the ability to spin his tails like a propeller, and thus fly. In Mario & Sonic at the Olympic Games and Mario & Sonic at the Olympic Winter Games, he is voiced by Amy Palant, but in Mario & Sonic at the London 2012 Olympic Games, he has been voiced by Kate Higgins. "Miles Prower", is a pun on "miles per hour".

Mario & Sonic at the Olympic Games
Tails participates in Olympic events in Mario & Sonic at the Olympic Games. He is a Skill type player, with skill and stamina being his best stats. Ironically, he is quite slow in this game, while he is quite speedy in the Sonic games.

Mario & Sonic at the Olympic Winter Games
Again, Tails participates in the Olympic events, this time in Mario & Sonic at the Olympic Winter Games, the sequel. Tails is a skill type player again. His stats are given on the official site as well.

Tails made an appearance in the adventure mode of the game for the Nintendo DS. In the game, he decides to help Sonic and Mario on their quest. Tails even makes remarks about Mario when he and Sonic first meets the fox, thus showing that Tails respects Mario due to his heroism (similar to how he respects Sonic).

Mario & Sonic at the London 2012 Olympic Games
In the third installment of the Mario & Sonic series, Mario & Sonic at the London 2012 Olympic Games, Tails makes another appearance as a playable character. He is a Skill type player in the Wii version like the two previous installments and is part of the Heroes in the 3DS version.

This is the first game in the series to introduce Kate Higgins as the new voice actress of Tails (who takes over from Amy Palant).

Mario & Sonic at the Sochi 2014 Olympic Winter Games
Tails appears in Mario & Sonic at the Sochi 2014 Olympic Winter Games. Like previous games in the series, Tails is a playable Skill type character.

Super Smash Bros. Brawl
In Super Smash Bros. Brawl, Tails appears in the background of the Green Hill Zone stage, as a cameo. He can occasionally be seen running through the loop in the background, alongside fellow Sonic characters, Knuckles the Echidna and Silver the Hedgehog. Tails also appears in the form of a collectible Trophy and Sticker, but doesn't appear anywhere else in the game.

Profile
''Sonic's buddy Tails the fox can fly thanks to his bushy tails, and he possesses a wide range of Skill-based abilities that will make him formidable in a wide range of events. He can jump and accelerate well, so he will be tough to beat in many races.''

Profile
''Miles "Tails" Prower is Sonic's best friend and always at his side. An ace pilot and mechanic, Tails returns to the Olympic Games with the Tailspin ability on the Wii and DS to spin his tails like a helicopter and propel himself in the air, as well as the Propeller Dash ability on the DS.''

Profile
''Sonic's buddy Miles Tails Prower is a fox that can fly, thanks to his bushy tails, and he possesses a wide range of Skill-based abilities that will make him formidable in a wide range of events. He can jump and accelerate well, so he will be tough to beat in many races.''

Trivia

 * Tails was thought to be an unlockable character, along with Sonic, in Super Smash Bros. Melee, but this turned out to be an infamous 2002 April Fool's prank set up by Electronic Gaming Monthly.
 * Tails, Dr. Eggman and Amy Rose are the only Sonic characters that have formal names.
 * In the Sonic series, Tails is one of the fastest characters, right behind Sonic, and tied with Shadow & Metal Sonic, being able to use his twin tails to move at supersonic speed. Despite this, Tails is strangely not a Speed-type character in the Mario & Sonic games.