After we defeated Ansem? We found out he wasn't Ansem...he was Xehanort's Heartless, and the real enemy we had to defeat was Xemnas, Ansem's nobody. [See how it gets complicated, Luke?]

A Nobody's what's left after the heart is consumed...if a person's heart is strong enough, the body and soul will combine to make a physical form and a strong Nobody. [...] There's a few of them here in Luceti, actually, including mine.