In case it hasn't been updated yet, my avatar is now Alex from the Golden Sun series.
You never get to actually fight him, but by the end of the second game, he has near infinite power (that's right, near-infinite, that's actually how his power is described). Also, he can control water using the power of his mind, including being able to create it
EDIT: Oh yeah, also, he can teleport, heal, and be incredibly manipulative and condescending.