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 sidekick to Sonic just like Luigi is a sidekick to Mario. In Mario & Sonic at the Olympic Games, he is voiced by Amy Palant.

''Mario & Sonic at the Olympic Games
Tails participates in Olympic events in Mario & Sonic at the Olympic Games. He is a Skill type player.

''Mario & Sonic at the Winter Olympic Games
Again, Tails participates in the Olympic events, this time in Mario & Sonic at the Olympic Winter Games, the sequel. It's unknown which type he'll be, most likely the Skill type again. His stats are given on the official site as well.

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.''Tails is an eight-year old fox boy and has a very high IQ. His mechanical ability is equal to that of Dr. Eggman. Although Tails' ability to build machines is invaluable to Sonic.

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, but doesn't appear anywhere else in the game.

Trivia

 * His full name, "Miles Prower", is a pun on "miles per hour".
 * He was originally going to be an Assist Trophy in Super Smash Bros. Brawl but was scrapped in favor of Shadow the Hedgehog for unknown reasons.
 * Tails was thought to be an unlockable character, along with Sonic, in Super Smash Bros. Melee, but this turned out to be an April Fool's prank set up by Electronic Gaming Monthly.