The Chimaera is a commander in the Chaos Army. She appears in Kid Icarus: Being of the Mirror. When met, Viridi explains to Dark Pit that 'although looking like a hideous 'it', it is in fact female.' She doesn't have chapter as of yet. She can understand the Chaos Kin's language and the angel's, so she acts as a translator for the Chaos Kin, although her English/Japanese/whatever langusge you're playing on needs practice, because her sentences often only make half-sense.
She is quite a difficult boss to defeat, with a lioness' head and body can slash with it's mighty teeth, the goat's head (it's weak spot) can't attack, but is where all the talking happens, and it's tail is a snake's tail, with a snake's head on the end. The tail make poisonous ranged attacks. After the fight, the Chimaera is petrified and taken back into the Chaos Vortex by the Chaos Kin, and lives on in the stone, just unable to move (it can still talk).