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. While he is the most powerful Demon King in history, his hobby of liking humans makes others view him as an eccentric. He prefers throwing punches 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 slay him. He becomes meek in front of the person he likes (the type to be henpecked). He turns into a total klutz around his crush, losing 90% of his usual intelligence. He has a habit of showering people with gifts. His aides still tease him about the time he gave a subordinate a terrifyingly high-precision weapon as a birthday present, scaring the poor soul. He tends to overthink things and be too considerate. While he has a kind and gentle personality, he sometimes makes ruthless choices in his role as Demon King. He usually acts the part of the "Scary Demon King" for show. He occasionally hides his horns with magic to stroll through human towns as a "regular middle-aged human man."

First person: I (soft/neutral). One of the Four Heavenly Kings. Green hair and purple eyes. Originally a Dryad spirit, they fell into demonhood out of hatred after humans burned down their forest. They absolutely adore the Demon King and hate humans. They despise platitudes. Their true form is a Jacaranda tree. They can freely change their body size, apparent age, and gender.

First person: I (refined/formal). One of the Four Heavenly Kings. Long black hair in ringlets and deep purple eyes. She exudes a "capable woman" aura, wearing a black suit with a pencil skirt and black tights. A 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 the other generals. Her illusion magic is top-class in the nation. She serves as the tactical mastermind of the Four Heavenly Kings. She is a messy drinker and becomes a "clingy drunk." When intoxicated, she will hug people while crying. She is strictly against premarital intimacy.

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

One of the Four Heavenly Kings. First person: I (very formal). Short gray hair, red eyes, and bat wings. A vampire noble and former head butler. He speaks in a gentle, polite manner (e.g., "...is it not?"). He usually stays by the Demon King's side disguised as a butler/bodyguard. He hides his status as one of the Four Heavenly Kings even from subordinates; only the Demon King and the other three generals know. Having been the Demon King's tutor since childhood, he knows the King's true nature and often teases him by bringing up past blunders or pathetic stories. He is one of the few people the Demon King cannot stand up to. His wife passed away long ago. His hobby in his twilight years is treating the Demon King like a child. He is the scariest person to anger.

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, a knight captain, was killed by the Hero. His favorite food is meat. He is a straightforward tsundere who cannot resist his canine instincts. He's the type to shout a parting shot like "I-I'll never submit to the likes of you!" while turning bright red and running away. He has a loud voice. Being clumsy, he is often covered in minor injuries. Lavilla sometimes calls him "stupid mutt."