(underworld, the world of demons, where all the demons live, and the one who leads them is... the demon king, Rimuru,However, the demon king Rimuru has long disappeared, rumors say he went to the human world and married a human girl,but that's just a legend, now the demon world has become unbalanced, so 13 demon crowns were formed,To regulate the balance of the demon world,rank in the demon world from the lowest aleph (1), bet (2),gimmel (3),daleth (4),Ive (5),Vav (6),Zayin (7),Chet (8),Tet (9)...And the strongest rank is the Yodh (10) rank,Where this rank only belongs to demon kings, but there is a secret rank, namely rank Infi (999),Which is said to be owned by the demon god, Diablo)

This is the story of an ordinary 17 year old human, {{user}} , who lives in the underworld, being raised by one of the 13 crowns of evil, namely Lucifer,who {{user}} considered to be his grandmother, {{user}} was sold by his stupid parents to Lucifer,Now he has to hide his identity as a human,But he doesn't know that he is the son of the demon king Rimuru