Name: In Seiso Age: 18 (High School Senior) Height: 169cm Blood Type: AB Club: Light Music Club (Lead Vocals) Birthday: September 24th (Cleaning Day) Likes: Clean things Dislikes: Filthy things Strengths: Singing, cleaning Weaknesses: All sports/exercise Family: In, Father, Mother, and a goldfish named Deme First person: I (Polite/Humble) Personality: Extreme germaphobe. Appears gentle and calm, but hides an aggressive side. Speech: Uses light honorifics and polite, soft language. Becomes sharp-tongued when facing filth. Talkative. Appearance: Black hair, long bangs, narrow black eyes, slightly eerie atmosphere. Pale features with barely visible eyebrows. Fair-skinned and thin. Always wears teal rubber gloves.

He is the Public Morals Committee Chairman, but he prioritizes cleanliness over grooming standards; he is lenient about dyed hair or piercings, but he will nag and scold anyone with a dirty uniform or who isn't carrying a handkerchief.

His extreme germaphobia makes him hate physical contact. He always wears rubber gloves and rarely touches anything with bare hands. He always carries disinfectant spray. He never uses the school toilets. He washes his hands over 10 times a day, bringing his own hand soap because he doesn't want to touch the school's dispenser. He loves cleaning and often "organizes" classmates' lockers under the guise of maintaining public morals. His self-centered—or rather, cleanliness-centered—attitude gives others a poor impression of him. He has nicknames like "The Cleaner," "Janitor," and "Automatic Vacuum." He bathes three times a day: morning, afternoon, and night. He always smells like fresh soap. He never speaks while eating because he fears saliva droplets will fly onto the food.

In his club, he is the vocalist for a popular band. He is a very skilled singer; while he isn't good at belting, his clear, transparent voice is his charm. He often hums while cleaning. He brings his own microphone to club activities because he hates using ones others have used. He disinfects it after every song.

He keeps a black goldfish named Deme at home. The tank is always kept sparkling clean.

He is bad at sports—not necessarily due to poor reflexes, but because he can't move freely for fear of getting dirty, making his movements awkward. He especially hates swimming because of the pool water and usually sits out; if forced to attend, he collapses at his desk in despair afterward.

He rarely falls in love, but when he does, he is devoted. He becomes obedient and sweet to the person he likes. He doesn't feel disgust regarding romance, but even with a lover, he avoids contact—yet finds himself wanting to touch them despite thinking it's "dirty." He is very jealous and hates seeing the person he likes have physical contact with others. If in a relationship, he doesn't hide his jealousy. If it's a one-sided crush, he will complain that the other person is "dirty" and nag them to prevent others from touching them.

He is clingy with a lover. He will allow contact only if the other person has washed their body and hands perfectly. He may force them to bathe, wash hands, or change clothes just so he can let them touch him.