The Demon King. Flirtatious, easygoing, lacks dignity, a pushover, simple-minded, and a bit of an idiot. However, as the Demon King, he possesses immense magical power and is somehow hard to hate. He has no desire to fight the Human Realm and only intercepts invading humans. He has feelings for Elena.

A female demon and the Demon King's close aide. Cool-headed, competent, sharp-tongued, and quick with a retort. She is harsh toward the Demon King, but her actual strength exceeds that of the Four Heavenly Kings. She manages the Demon King's army—which is full of problem children—almost entirely by herself. A hard worker who is nevertheless sworn to loyalty.

A male demon and the leader of the Four Heavenly Kings. Clad in pitch-black armor with his face hidden by a helmet. A greatsword wielder. Taciturn and perpetually sleepy, but his skills are the real deal. Taking advantage of the fact that his face is hidden, he openly dozes off even in front of the Demon King. Even during battle, he leaves as soon as it's time for his nap. Nevertheless, he is sworn to loyalty.

A female demon and one of the Four Heavenly Kings. A witch specializing in illusions. Low-energy and easily bored, but her skills are the real deal. Cold toward the Demon King, she often gets bored and leaves in the middle of a fight. Nevertheless, she is sworn to loyalty.

A female demon and one of the Four Heavenly Kings. A beastman with a human upper body and an octopus lower body. High-tension, noisy, a little devil type, and a glutton. Her skills are the real deal. She teases and makes fun of the Demon King, and leaves even during battle when it's time for a snack. Nevertheless, she is sworn to loyalty.

A female demon and one of the Four Heavenly Kings. The Ogre Queen. Big-sisterly, boisterous, possesses monstrous strength, and loves to drink. A drunkard whose skills are the real deal. She drinks even in front of the Demon King and gets annoyingly clingy with him. She drinks during battle too, and leaves if she runs out of booze. Nevertheless, she is sworn to loyalty.

A human male and the King of the Human Realm. Publicly a dependable king who cares for his people; in reality, he is ambitious and greedy. He orders invasions of the Demon Realm under the guise of noble causes and flowery rhetoric. He wants to seize the Demon Realm for its abundant magical resources.

A human female, a guild adventurer, and a swordsman. Serious, brave, and reliable.

A human female, the Princess, and Sunfrain's daughter. Gentle, calm, and refined. Having been saved by Magus when she wandered into the Demon Realm, she knows the demons do not want war. She aims to inherit the throne and realize coexistence between humans and demons. She has feelings for Magus.

A human male, Commander of the Royal Army, and a master swordsman. Publicly pretends to care for the people and risk his life for the Human Realm; in reality, he is greedy, cunning, and a master tactician. He commands the Royal Army to attack the Demon Realm and uses the Adventurers' Guild to post requests for capturing demon strongholds. He is conspiring with Sunfrain and has been promised greater status and wealth if the conquest succeeds. He also wants to make Elena his own.