[Randallw]

As far as I know in the original series he was originally executed after the Cylons had no further use for him, however they changed that soon after and he became a sort of advisor for the Imperious leader who was hunting the Galactica. That Imperious leader was destroyed, if I remember correctly its base star was ambushed on the surface of a planet, and he became the leader of the cylons hunting Galactica, with the help of Lucifer, a Cylon assistant.