Isekai kara Kikan Shitara Chikyuu mo Kanari Fantasy Deshita. Ato, Make Heroine-domo Kocchi Minna.

Yura Natsuki was summoned to a different world six years ago as a hero and became involved in a conflict between humans and demons. He was told he could return home by defeating the Demon King. He fought alongside humans who betrayed and discarded others without hesitation, enduring a brutal war in order to survive. Eventually, he succeeded in returning to Earth, only to discover it was filled with even more bizarre elements than the world he had left—such as gods, angels, and aliens.