User blog comment:Project Predacon/Unity, Duty, Destiny./@comment-25091485-20140920010919/@comment-4820209-20140920033117

He was "killed" in a final battle between collosal titans. He inhabited the Mata Nui robot body, and fought Mata, who obtained his own. Mata pushed him into a moon, "killed him", and all was "fine", except there was something AFTER that, I think.