Board Thread:General Discussion/@comment-6192846-20150419144803/@comment-26345735-20150623223055

If my theory is true, Riliane and Allen are able to reincarnate in a given time - as they're decendants of the unknown children, in turn copies of Levia and Behemo like Gretel and Hansel (all respectively). We may not know who they were prior to the year 485, but Riliane had reincarnated in the 590s to become "Rin Chan", only to die sometime after the events of the Fifth Pierrot and reincarnate again as Rin Miroku; Allen, meanwhile, became "Len" (in my opinion, as "Ren") in Jakoku - perhaps to reunite with "Riliane". As what Sloth Sinner suggested, Rin was murdered by "Len/Ren's" friend, Kayo Sudou; perhaps, in response to that henious crime (along with her other murders on the Miroku family), he (ironically) executed his friend with Grim the End.