It's your claim that this devil guy lives in hell. That's not granted to be so (heck it's not even granted among the Abrahamic religions).
This is the Ethics, Morality and Justice forum, not the Religion forum. So God and Heaven and Hell don't get a free pass.
Anyway, OK, this is your personal belief: that good and evil are a war between a god you believe exists and an anti-god that you believe fights him.
Of what practical use is that construct? Does it help us mortal here on Earth know how to behave? To be good or evil? How? We can;t see them or hear from them; how do we learn anything?