[@InfiniteEmbers] Except she's not in a constant state of regeneration; her body only begins to heal itself when she should have died. And a supernatural force isn't the same as a physical death, so her body wouldn't need to heal itself, so nothing would happen. She's got no soul, no life force, I would argue- she should have died a hundred times over at this point. So there's nothing to take, I think- how would that work?

EDIT: Unless, somehow, he instead took her pain away, even temporarily, and gained from that, rather than life force or whatever you want to call it?