Read What a Bountiful Harvest, Demon Lord!

[By the Author and Studio that brought you <The Greatest Estate Developer>!]

I've become the Demon Lord, the final boss in a game, but...

If I invade the human world? I'll be slain by the max-level protagonist I raised.

If I stop the invasion? I'll be devoured by my starving demon generals.

...Therefore, the only answer is farming.