What a Bountiful Harvest, Demon Lord!

풍작이에요, 마왕님! • Pungjag-ieyo, Mawangnim! • Небывалый урожай, повелитель! • วิถีชาวนาของราชาปีศาจ • 大丰收呢，魔王大人 • 豊作ですよ、魔王様！ • 魔王大人，大豐收！

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.