Complex sentence: Believing him to be a captured human soldier with amnesia, Zor is debriefed and then made a member of Dana's squad and becomes a Hovertank pilot with the very same ATAC unit he had fought with previously.
Split into simpler sentences: Believing him to be a captured human soldier with amnesia, Zor is debriefed and then made a member of Dana's squad. He becomes a Hovertank pilot with the very same ATAC unit he had fought with previously.