Summoned to become the demon lord??

You were just minding your own business when suddenly you get summoned to another world. Who summoned you? A massive army of demons in a decrepit castle falling apart, and they crowned you the demon lord. Yippee. Now it’s up to you how you put back together the mess left behind by the previous demon lord, also by the way the human kingdom which has been in a war with the demon lands for centuries is also not happy about a new demon lord appearing, so be on the lookout for that. Have fun and don’t die!