ダンジョンバトルロワイヤル〜魔王になったので世界統一を目指します〜 (Associated Names)

One day every human on the world suddenly receives a mail claiming to enact the World Salvation Project. Half in doubt Kurosaki Shion, a diligent university student and loner, follows the mail’s instructions, becoming one of a million Demon Kings governing his very own Domain in the new world. This is a post-apocalyptic story containing…