User blog comment:IamJakuhoRaikoben/Chapter 451: Fairy Heart, Review./@comment-3045936-20150907154703/@comment-3045936-20150907155840

Well, maybe Anhkseram isn't a god exactly, but the original form of magic aka the Darkness that magic came from. So that would explain how Mavis's body in a Lacrima has an limitless supply of Magic Power. So I think Ankhseram is the One Magic, and is its God as well. As we know Earthland magic is infinite in amount unlike Edolas. So maybe to kill himself and Aco he needs the original state of the One Magic. As if he could use it he could kill anything he wouldn't need slayer magic to deal with Aco, nor would it matter if he is immortal.