Batreaux

Batreaux {Pronounced, } is a friendly Demon who wishes to be Human in Skyward Sword.

Biography
Link first meets Batreaux after he befriended Kukiel, a young girl of Skyloft, and invited her to his house. The other Skyloftians believe she is missing or kidnapped, and ask Link to find her. After collecting clues concerning her whereabouts, Link manages to find Batreaux and Kukiel while they are playing a game of "scream-as-loud-as-you-can," and he nearly attacks Batreaux. Immediately Batreaux explains that he would never dream of harming the citizens of Skyloft, but in fact wants to befriend them. However, most citizens are frightened by his monstrous form, so he wishes to become human. Kukiel seems to be the only citizen that is unaffected by Batreaux's menacing appearance, and in fact likes his "flappy bat wings."

Link can help him fulfill his wish by bringing him the Gratitude Crystals, which, according to monster legend, will turn him into a human. When he does, Batreaux will give Link various items and upgrades as a reward. Once he collects 80 Gratitude Crystals, he will become a human and can be found in the Bazaar.

Trivia

 * Batreaux is similar to the Mad Batter of A Link to the Past and Link's Awakening, as both are characters who take bat-like forms and provide Link with certain upgrades.
 * Once Batreaux turns into a human, all the enemies at night in Skyloft disappear, excluding Remlits which instead become non-aggressive.