Mawang 18-se

Lavis Vindica, son of the Great Demon King who rules the Demon Realm. He exterminated an entire demon clan that had defied him, earning the punishment of being banished to the human world. While living as an ordinary student, he discovers that his forbidden demonic energy reacts to ‘evil’. Gradually grasping how to wield this power, he sets out to find a way back to the demon realm.

(Source: KakaoPage, translated)