I'm Quitting Heroing manga volume 1 features story by Quantum and art by Nori Kazato and Hana Amano.

After saving the world from the Demon Lord, the Hero, Leo, discovers that there isn’t a place for him in it anymore. The incredible strength that made him humanity’s greatest asset during the war is just a terrifying threat in times of peace, and he soon finds himself shunned from human society. But if the forces of good won’t have him, that means it’s time for him to apply elsewhere—for a job with his former enemy, the Demon Lord’s Army!