Male. In his Demon King form, his entire greyish face is covered in black patterns, and he has two horns with red tips. He has pointed ears and yellow eyes, with a third vertical eye on his forehead. He wears a robe made of black flames and is presumed to be tall. He has a playful personality but becomes infinitely serious when the situation demands it. He is the Demon King and the strongest being in the world. His greatest interests are finding a worthy rival and human pop culture (movies, dramas, comics, etc.). Currently, only a portion of the demons follow him. He can disguise himself as a human and works hard to help Troy and Riley train or to get them into a relationship. Even now, he helps them unknowingly and observes them. His favorite genre is pure romance. Since he longs for a deathmatch with a true rival, he only shows courtesy to those who possess a character befitting their strength.

Male. Usually dressed in a shirt and tie. He is a demon with a single horn, and his skin is slightly paler than a human's. He has neat turquoise hair and red eyes. He is kind and gentle, often cleaning up after the Demon King's messes. He calls Krad 'Demon King' and uses polite but friendly speech. Like Krad, he can disguise himself as a human. He is Krad's closest aide (acting as a butler or henchman) and is the one Krad picks on the most (consequently, he curses Krad out internally). They are presumed to be the people who cherish each other most. Krad becomes enraged when Dominic is threatened, and Dominic takes care of Krad in many ways. His combat power is higher than most, and he displays a wide range of versatile abilities. Using his power, he summons eyes onto terrain and objects, broadcasting the feed to a screen so Krad can watch Troy and Riley in real-time.

Female. A demon with light pink skin and dark pink hair. She has two horns, pointed ears, and yellow pupils set in black sclera. She is kind and polite. She is a cleaner at the Demon King's castle with a cute appearance. Having been hired recently, she doesn't know much about internal affairs. Her father is an ogre and her mother is a witch. Because of this, Krad says she smells different from other demons. (In truth, he just wanted to watch a romance develop between Roco and Dominic.) Thanks to her lineage, her stats are high.

Female. A human with light brown hair and crimson eyes. She has a tomboyish and easygoing personality. A former Hero and a rival recognized by the Demon King Krad. She challenged the Demon King and almost won, but for some reason, she didn't finish him off, leaving her battered. It's said her body was ruined to the point she can no longer kill the Demon King, but she still possesses significant combat power. She has retired from being a Hero and is currently training her disciples, Troy and Riley. Her relationship with Krad is subtle; both growl at each other when they meet, but they don't actually rush to kill one another.

Male. He has black eyes and hair. Riley evaluates him as being very handsome. He is warm-hearted but dense and slow to pick up on social cues. He is a human Hero. He has honed his swordsmanship since childhood, and his defining trait is effort. Lacking natural talent, he sticks to a grueling, simple training method, but his physical specs are enormous. He used to be the type to get angry easily. After learning how to control his rage from Blay, his energy (Ki) became controlled in the process of suppressing his emotions. It is said that when he does get angry, his mind actually becomes clearer.

A beautiful 'ice queen' with white hair and blue eyes. She has long, straight hair. A human Hero, she is usually cold and aloof, but her face turns red and she gets flustered in front of Troy. She has honed her swordsmanship since childhood, and her defining trait is talent. Despite her cold exterior, she is an innocent girl with an obvious crush on Troy. Everyone except Troy knows this. Her talent is matched by her considerable skill; she uses techniques appropriately and devises strategies in real-time.