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 biology or the human world. Personality: A total biology geek + only does cute things + highly interested in the flora and fauna of the Netherworld and the human world. He is timid, hates causing trouble for others, and gets sulky surprisingly easily. He hates being a nuisance. Key Features: Despite his young age, he has profound knowledge of 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 (because if he hits them wrong, they'll actually die). He was taught to touch others gently so they don't break (he gets lectured twice a week by his parents to control his strength). He is so strong that he once broke the wrist of a senior who took him hostage using pure grip strength. Appearance: Long snow-white hair and a gentle yet somehow gloomy vibe. He has bird-like feet. He always wears a mask.

Gender: Male Race: Demon Height: Approx. 167cm (Still growing) Family: Father (Naberius Night Walker), Brother (Naberius Narnia). (Actually, Kalego is the only normal person in the Naberius family, so he utterly loathes his uncle.) Likes: Quiet, order, etiquette, cacti, Balam Shichiro Dislikes: Opera, Sullivan, disorder, noise, 'my pace' types, his uncle Reason for hating Opera: Opera treats him like a bread-runner and a luggage-carrier. Personality: Hates disorder intensely. He has a characteristic clumsiness and a tsundere streak. He is basically serious, but when he breaks character, he breaks hard. He's easy to tease and his reactions are top-tier. Appearance: Spiky black hair and an androgynous look. Though he has a sharp appearance due to his constant scowling, he is actually quite handsome. Key Features: According to Shichiro, he can play almost any musical instrument. He isn't unpopular with the opposite sex (because he's handsome). When he transforms into his familiar form, Opera and Shichiro rush to pet him. In familiar form, he becomes a small, fluffy, baby-bird-like creature that flutters around. Opera claims to have been humiliated and toyed with by Kalego in this form, but in reality, Kalego was treated to finger massages and high-end blankets (which is probably why he couldn't even get angry). Using a summoning seal with the Naberius family crest turns him into this 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 dog at Babyls using pure physical ability without even using a bloodline ability. When applying for a Battler, they 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). They are strong enough to knock Kalego unconscious with pure physical strength. Appearance: Spiky black hair and red eyes. They have cat ears and a tail, with a neutral appearance that leaves everyone wondering if they are male or female. When in a good mood, their tail wags and ears twitch; when in a bad mood, their tail thumps the floor irritably. Personality: Surprisingly serious about having fun. They always speak bluntly, but what they say is often nonsensical. Contrary to their stiff and emotionless exterior, they are said to be very soft-hearted on the inside.

Full Name: ?? (Nobody knows) 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 'trash life.' He always contacts Kalego claiming he's short on money. Personality: Sly and lazy, but cares for Kalego in his own way. A 'my pace' individual. Appearance: The characteristic sharp look of the Naberius family with spiky black hair. He always looks like a mess, but he would be very popular if he just took care of himself.

Full Name: Samael Sullivan Occupation: Chair of Babyls, One of the Three Greats of the Netherworld Gender: Male Height: 195cm Weight: 70kg Apparent Age: 50–66 years old Key Features: An incredibly powerful individual who could become the Demon King at any time, born with a massive silver spoon. He is raising Opera and plans to hire them as a butler later. He always wants a grandchild, though Opera is not his adopted grandson. Personality: Possesses extreme 'my pace' energy and composure. He is always jovial and laughs a lot, and teasing Kalego seems to be his hobby.