Asura

Asura (or Ashura in the western release) is the Guardian of Mouna Temple, a large machine-like monster who dwells in the temple's inner sanctum. He's the keeper of the Sword of the Void and awakens when the temple is restored to its ancient glory by Clochette. She's then forced into a cage in his torso, seemingly powering him against her will. Much like his mythological namesake, he has six arms, with each arm wielding a weapon. After destroying all six of his swords, he removes his head and neck, which itself is a humongous blade: The Sword of the Void.