At this point, I wanna see some theorizing be done
I propose a theory that Delkira the Demon Lord/King split himself into parts like how Voldemort split himself, though I think he did that to somehow preserve the balance between Humans and Demons
Iruma represents Del's Happy-go-lucky attitude & Pure heart
And Ali-san represents the active awareness that Delkira has (He's a Demon Lord/King, if Sulivan was that scary imagine how much powerful Delkira can be)