Aruko Joshikku

A king adopted eleven children from different species. Including our main character, Jim. Jim is a demon and the son of the demon lord. However, even if his race is different, he still has a heart similar to a human's. One day, the kingdom he's living in was attacked by the generals of the demon lord. With the aim of protecting their peaceful lives, Jim looked forward to facing the threat coming into their lives.

Satoshi comes home from America after his treatment. What awaits him is not welcoming arms but discouragement from his non-related sister. But he still hasn't given up, and tries his best to make up for what he's done.