The wings disappear at the end when The Magic Goes Away. They summon these wings in battle, mostly just because it looks awesome. Nearly everyone in Baten Kaitos is a Winged Humanoid who can make said wings appear or disappear at will.This lowers her HP, but increases her attack power, turning her into somewhat of a Glass Cannon. Inverted somewhat in Atelier Iris: Eternal Mana - When weaker due to running low on mana thanks to being an Artificial Human, Lita sprouts a pair of white angel wings in battle.In this state, they can access far more of Blackmist's divine power than normal. In the Armed With Wings series, the titular chosen ones/incarnations of Blackmist are given the ability to access a powered up form in which their shadowy form becomes white instead of black, and they grow a pair of white wings.
His brother Darc is an inversion he begins the game with wings and spellcasting abilities, but shortly after his wings are torn off, he finds a human sword and decides to incorporate human martial arts into his fighting style. Kharg gains the ability to learn magic early in the game, but doesn't know why when it's revealed later in the game that his magic is a result of his Half-Deimos lineage, the shock causes him to grow a pair of wings, which he rips from his back in disgust, so he's both a justified case and an avertion.