A high school student with an exceptionally strong sense of justice and competitive spirit, Shibuya Yuuri, one day tries to help a former middle school classmate in a park but ends up beaten by delinquent high schoolers, nearly having his face shoved into a public toilet bowl. When he opens his eyes, he finds himself transported to another world. He is told that he was born with the soul of a king and is the ruler of the "Kingdom of Demons," and as the leader of the demon tribe, he must fight against humans. While struggling with cultural and value differences, he grows into a novice Demon King, relying on his innate sense of justice and pacifism. This is a fantasy novel.