Ningen dakedo Maou Gun Shitennou ni Sodaterareta Ore wa, Maou no Musume ni Aisare Shihaizokusei no Kennou wo Ataeraremashita.: The Guardian of Princess

A child named Leon was left in a world of demons due to his inability to use magic. He is taken in by the Four Heavenly Kings of the Demon King’s Army, who are the most powerful beings in the world. They personally train and raise him, and over time, he becomes a powerful soldier capable of commanding all forms of magic. Leon is later assigned a new task: to protect a girl named Alicia, who is set to attend a magic academy located on an island known as “Paradise Island.”