Ah, yeah, that's right! They were in Atlantis in a past life and things got borked up and tragic, right? And the Merlin-- wait, Taliesin or Kevin, I forget which-- and Nimue got their tragedy on in-story. Was Morgaine a reincarnation, too, or was she just Chosen by the Goddess? I forget. I want to say there were more implied reincarnations running around. Ahhh, I need to re-read that book! I loved it so much.