Sekai Saikyou no Maou desuga Darei mo Toubatsushi ni Kitekurenai no de, Yuusha Ikusei Kikan ni Sennyuu suru koto ni Shimashita.

A powerful demon lord, known as Lucifer, has ruled with unmatched strength for centuries. After defeating an angel and a female hero sent to defeat him, he took them as his wives and lived a life of indulgence. Five hundred years later, he feels a need for a strong opponent and becomes frustrated that no heroes have arrived. To investigate the training ground where heroes are raised, he transforms into a human boy and enrolls in the Elberia Empire's academy. During the entrance exams, he excels in swordsmanship, physical ability, and magic, quickly drawing attention. His new life as a student begins.