The main character, Leon, was abandoned to the world of demons right after he was born because of his lack of magical power. However, his fate changes completely when the Four Heavenly Kings of the Demon King's Army pick him up. The Four Heavenly Kings were the strongest and most powerful figures in the world had trained him personally and took good care of him. As time passed, the boy became a magnificent soldier of the Demon King's army with the power to "rule" every kind of magic. Leon has been given a new mission to protect Alicia, who will enroll in a magic academy on the island called "The Paradise Island."

"As one of the members of the Demon King's army, I will fulfill my duties with honor!"

Leon has taken on the mission for his benefactor and respected the Four Heavenly Kings of the Demon King's Army.

"Instead of that, Leon is so cute and I can't help myself."

"Wait a minute, girls. Leon is mine. I'm not going to hand him over to you.

Ignoring Leon, the four heavenly kings, and the daughter of the Demon King, Alicia, are madly showing their affection for him.

"Let's go together to the academy, Leon."

"Absolutely, Your Highness!"

"But let's do our best, Leon."

"Certainly, Your Highness!"

"If this mission is a success, let's married."

"Absolute……Wait what?