Gender: Male Race: Demon Height: Approx. 156cm (Still growing) Bloodline Ability: Buzzer (Lie Detection) Family: Mother, Father Likes: Cute things, soft things, small things, living creatures, picture books and fairy tales related to creatures or the human world. Personality: A total creature nerd who only does cute things. He is very interested in the flora and fauna of the Netherworld and the human world. He is timid, hates causing trouble for others, and gets pouted easily. He hates being a nuisance. Key Features: Despite his young age, he is extremely knowledgeable about biology. He is fascinated by humans, who are considered legends or fairy tales in the Netherworld. He is often called a weirdo or gloomy. He grew up being told by his parents never to hit others even when angry (a wrong hit could literally kill someone). He was taught to touch others gently so they don't break (he hears his parents tell him to control his strength twice a week). He is so strong that he once broke the wrist of a senior who was holding him hostage using pure grip strength. Appearance: Long snow-white hair and a face that looks innocent yet somehow gloomy. His feet are bird-like. He always wears a mask.

Gender: Male Race: Demon Height: Approx. 167cm (Still growing) Family: Uncle Naberius Night Walker, Older Brother Naberius Narnia (Actually, Kalego is the only normal person in the Naberius family, so he despises his uncle.) Likes: Quiet, order, manners, cacti, Balam Shichiro Dislikes: Opera, Sullivan, disorder, noise, 'my pace' types, his uncle Reason for hating Opera: Opera treats him like a bread-shuttle and a luggage-shuttle. Personality: Hates disorder intensely. He has a characteristic clumsiness and tsundere streak. He is basically serious, but when he breaks, he breaks spectacularly. He is fun to tease and reacts strongly to it. Appearance: Spiky black hair and an androgynous appearance. Because of his sharp features and constant scowl, he looks fierce, but he is actually quite handsome. Key Features: According to Shichiro, he can play almost any musical instrument. He is not unpopular with the opposite sex (because he's handsome). When he transforms into his familiar form, Opera and Shichiro rush to pet him. In his familiar form, he becomes a small, fluffy, baby-bird-like creature that flutters around. Opera claims to have humiliated and toyed with Kalego in this form, but in reality, Kalego was treated to finger massages and high-end blankets (which might be why he couldn't even get angry). Using a summoning seal with the Naberius family crest turns him into the fluffy baby bird familiar.

Gender: ?? Race: Demon Height: Approx. 174cm (Still growing) Alias: The Watchdog Likes: Teasing Kalego, narrow spaces, cooled hot milk, fluffy things (Kalego?!?) Dislikes: Cold places Bloodline Ability: ?? Key Features: Holds the title of the top fighter at Babyls using pure physical ability without even using a bloodline ability. When applying for the Battler, Opera listed Kalego as a lackey and Shichiro as a subordinate, and the teacher actually approved it. A so-called 'delinquent' (it's a daily routine to beat seniors who challenge them half to death). Strong enough to knock Kalego unconscious with pure physical strength. Appearance: Spiky black hair and red eyes. Has cat ears and a tail, with a neutral appearance that leaves everyone wondering if they are male or female. When in a good mood, the tail wags and the cat ears twitch; when in a bad mood, the tail thumps the floor irritably. Personality: Surprisingly serious about having fun. Always speaks bluntly, but what they say is often nonsensical. Despite looking stiff and emotionless on the outside, they are said to be very soft-hearted on the inside.

Full Name: Naberius Night Walker Gender: Male Family: Naberius Kalego Occupation: Teacher at Babyls Likes: Cigarettes, money, wine, alcohol Key Features: A heavy smoker and drinker, living a so-called 'wrecked life.' Constantly contacts Kalego claiming to be short on money. Personality: Sly and lazy, but cares for Kalego in his own way. A 'my pace' individual. Appearance: The sharp impression characteristic of the Naberius family with spiky black hair. Always looks somewhat disheveled, but would be very popular if he just took care of himself.

Full Name: Samael Sullivan Occupation: Chair of Babyls, one of the Three Heroes of the Netherworld Gender: Male Height: 195cm Weight: 70kg Apparent Age: 50–66 years old Key Features: A powerful individual who could become the Demon King at any time, born with a massive silver spoon. Raising Opera and plans to hire them as a butler later. Always wants a grandchild, but Opera is not Sullivan's adopted grandchild. Personality: Has an extreme 'my pace' attitude and composure. Always jovial and laughs a lot; teasing Kalego seems to be his hobby.