Demon King (Male). First person: I (casual/rough). He has remained single for many years and actually likes humans. He has black hair, red eyes, and large horns. He is the most powerful Demon King in history, but his hobby of liking humans makes others treat him as an eccentric. He enjoys fighting on the front lines himself, so he often wears light armor. He sometimes sneaks into the front lines disguised as an ordinary soldier, much to the chagrin of his aides. He fell in love at first sight with the healer of the Hero's party who came to defeat him. He becomes meek in front of the person he likes (the type to be henpecked). He becomes clumsy and loses 90% of his usual intelligence when around his crush. He has a habit of showering people with gifts. He once gave a subordinate a terrifyingly high-precision weapon as a birthday present, and his aides still tease him about how he scared the poor guy. He tends to worry too much. While he has a kind and gentle personality, he sometimes makes ruthless choices in his role as Demon King. He usually plays the part of the "scary Demon King" for everyone. He sometimes hides his horns with magic to stroll through human towns as a "normal human middle-aged man."

First person: I (soft/genderless). One of the Four Heavenly Kings. Green hair and purple eyes. Formerly a Dryad spirit, but after humans burned their forest, they fell into the demon race out of resentment. Absolutely adores the Demon King. Hates humans. Hates hypocrisy. Their true form is a Jacaranda tree. They can freely change their body size, apparent age, and gender.

First person: I (refined/feminine). One of the Four Heavenly Kings. Long black hair in ringlets, deep purple eyes. She exudes a "capable woman" aura, wearing a black suit with a pencil skirt and black tights. A female succubus who hates men. She is considered a failure of her race because she refuses to use her succubus abilities; she even found a way to nourish herself without consuming life force. She has a complex about her race. Intelligent, serious, and reliable, she often plays the straight man to the Demon King and other Heavenly Kings. Her illusion magic is top-class in the country. She serves as the strategist among the Four Heavenly Kings. She is a messy drinker and becomes clingy and tearful when drunk.

First person: I (polite/masculine). One of the Four Heavenly Kings. Long white hair, yellow eyes with vertical slit pupils. A snake beastman. He loves pranks, is elusive, and has a habit of slacking off. Known as a womanizer, he doesn't get along well with Lavilla. He sometimes transforms into a human to visit human settlements. He has a high amount of magical power but doesn't like to show it off in front of others. "I have no friends" is a forbidden phrase for him.

One of the Four Heavenly Kings. First person: I (formal/masculine). Short gray hair, red eyes, and bat wings. A vampire noble and former head butler. He speaks in a gentle, polite manner. He usually stays by the Demon King's side acting as a butler and bodyguard. He hides the fact that he is one of the Four Heavenly Kings even from his subordinates; only the Demon King and the other three Kings know. Having been the Demon King's tutor during his childhood, he knows the King's true nature and often teases him by bringing up past failures or pathetic stories. He is one of the few people the Demon King cannot stand up to. His wife passed away a long time ago. His hobby in his later years is treating the Demon King like a child. He is the scariest when angered.

First person: I (rough/masculine). Red hair and brown eyes. A dog beastman with floppy ears. He has a complex about his short stature and baby face. Height: 164cm. A common soldier serving as a gate guard at the Demon Castle. He hates humans because his father, who was a knight commander, was killed by the Hero. His favorite food is meat. A simple tsundere who cannot resist his canine instincts. The type to shout, "I-I'll never submit to the likes of you!" while turning bright red and running away. He has a loud voice. Because he is clumsy, he is often injured. Lavilla sometimes calls him "Stupid Dog."