Seiko is a teenage girl with below-average height and build. She has light brown eyes and long brown hair (colored orange in the manga adaptation) that she styles into two curls on both sides of her head, just beneath her ears. She also wears a blue barrette on the left side of her head. Seiko has a natural kitty mouth/smile, which is especially noticeable when she's being devious and/or perverted. She wears the standard Kisaragi Academy Senior High female uniform consisting of a tan colored sailor outfit with a blue collar, light blue cuffs, yellow ribbon held by a blue brooch, blue pleated skirt, black knee-high socks and white uwabaki slippers with blue stripes near the soles. Her student ID is pinned on the top left side of her skirt. Seiko is an extremely cheerful and energetic girl who enjoys playing around with her friends. She often comes across as immature and crass and makes over-the-top outbursts that surprise everyone around her, but her friends are able to put up with it. She generally tries to maintain this personality even while trapped inside Heavenly Host, though the grim reality of their situation nearly causes her to suffer from an emotional breakdown several times. She is not without a responsible side, however, which she developed after her mother disappeared two years ago in order to support her father and care for her three younger siblings. She easily becomes upset whenever anyone takes her feelings towards her mother's disappearance lightly. In the game, it is described that she has a perverted side.

Naomi is a teenage girl of average height and below average build with short, brown hair and brown eyes. She wears the standard Kisaragi Academy Senior High female uniform consisting of a tan colored sailor outfit with a blue collar, light blue cuffs, yellow ribbon held by a brooch, blue skirt, black knee-high socks and white uwabaki slippers with blue stripes near the soles. Naomi is generally a bright and cheerful, if stubborn, teenage girl. A tomboy, she often feels the need to take charge of everything she is involved with, which usually causes her to butt heads with Satoshi Mochida. This behavior hides a more "girlish" side to her that enjoys shopping and grooming herself like other average girls of her age, which shows itself whenever she plays with her best friend, Seiko Shinohara. She tends to let her emotions control her actions; when stressed, scared, or upset, she is prone to acting like a spoiled brat who whines, throws childish tantrums, and lashes out at everyone around her. However, she is very self-aware of herself during such intervals but has extreme difficulty stopping herself from acting in such an immature manner, which causes her to feel guilty whenever she regains control of herself.

Ayumi is a teenage girl of below average height and build with blue eyes and long dark blue hair styled into two pigtails, held with red hair ties. She wore the standard issue Kisaragi Academy Senior High female uniform consisting of a tan colored sailor outfit with a blue collar, light blue cuffs, yellow ribbon held by a blue brooch, blue pleated skirt, white knee-high socks and white uwabaki slippers with blue stripes near the soles. Her student ID is pinned on the left side of her shirt. Ayumi is a tough girl with great interest about the occult, and likes to scare her friends with ghost stories. However, this is her way to hide her easily frightened personality, even rivaling that of her classmate, Satoshi Mochida. However, she can be brave when it's needed, as demonstrated when she returned to Heavenly Host to rescue the survivors, despite the possible consequences. She was a fan of Naho Saenoki and her works until the recent events in Heavenly Host. But despite her occasional selfish or jealous actions, Ayumi really does care about her friends, even more than herself, and hates it when people go out of their way for her.

Yui is a young adult of average height and weight. She has brown, medium short hair and purple eyes. She is seen wearing cyan earrings, a pink blazer with a hot pink shirt with underneath, an indigo skirt, black high-heels and a necklace with a panda ornament, mentioned by Yoshiki Kishinuma as the "Floppy-Droopy Panda necklace." Yui is a young teacher who has just started her career at Kisaragi Academy. She is cheerful and friendly to her students, especially to Ayumi Shinozaki, who compares Yui to a sister, and plays pranks along with her. Even though she is enthusiastic, she believed that she was a bad teacher, until Hajime Yamazaki explained to her the true meaning of teaching. Throughout the events in Heavenly Host, Yui proves to be a brave and determined individual that deeply cares for her students, even more than herself.