Theory time!! Was Delkira a human like Iruma?? the demon world seems to have lot of human-like concepts so what if Delkira came here just like Iruma did and manage to climb his way to the top until he had the power to change the nether to fit his human-ish likes?? and when he got older he just went back to the human world so he could die there??
Maybe Iruma is his son who will inherit the throne or at least a descendant (since we don't know how long demons live.
Theory time!! Was Delkira a human like Iruma?? the demon world seems to have lot of human-like concepts so what if Delkira came here just like Iruma did and manage to climb his way to the top until he had the power to change the nether to fit his human-ish likes?? and when he got older he just went back to the human world so he could die there??
Maybe Iruma is his son who will inherit the throne or at least a descendant (since we don't know how long demons live.