A 14-year-old female demon. She is Tanjiro Kamado's younger sister. After nearly burning to death in the sunlight, she conquered the sun, allowing her to remove her bamboo muzzle and speak. Her language skills are still at a toddler's level, but she can communicate to some extent, though she stutters and sometimes repeats what others say like a parrot. Inosuke has been brainwashing her into learning to write by making her repeat "Inosuke." While she is usually as pure and innocent as a child, she turns terrifyingly aggressive and brave once a battle begins to protect her brother and allies. Although her mental age has regressed, her fighting instinct and protective will remain intact; she fights back fiercely with sharp kicks and shows overwhelming tenacity, fighting until her body breaks if her brother is in danger.

An 18-year-old female, 151cm, 37kg. She is the younger sister of Kanae Kocho and the Insect Hashira of the Demon Slayer Corps. She uses Insect Breathing. Her hobby is telling ghost stories. She likes ginger preserved in soy sauce and dislikes furry animals. She is well-versed in pharmacology and is the only one among the Hashira who kills demons using poison. Along with her sister, she serves as a medical officer within the Corps, using her residence, the 'Butterfly Mansion,' as a ward. She has a beautiful face and atmosphere, as well as an excellent physique. Her black hair is characterized by a two-tone style with purple-dyed ends, and she has purple eyes. She wears a short, plain white haori and leggings with a pattern mimicking insect wings. She has a short-tempered, emotional, and blunt personality. She developed the poison used to slay demons and is Kanao's benefactor.

A 16-year-old female, 156cm, 46kg. A member of the Demon Slayer Corps. She uses Flower Breathing. Her hobby is blowing soap bubbles from morning till night. She likes things made by Aoi and Ramune. She has black hair, purple eyes, and a refined yet cute appearance. She rarely expresses emotion. She is Shinobu Kocho's Tsuguko.

A 17-year-old female. Her rank in the Demon Slayer Corps is unknown. Her Nichirin Sword is blue, and she uses Water Breathing. She has black hair, blue eyes, and wears her hair in twin tails secured by blue butterfly-shaped ornaments. She wears a medical gown over her blue-tinted uniform. She works as the head nurse at the Butterfly Mansion. She has a strict and strong-willed personality, often wearing an angry expression and using a blunt tone, but she is secretly warm-hearted. She has a strong sense of responsibility, quietly carrying out her duties, and is kind to those she doesn't know.

A 13-year-old female nurse at the Butterfly Mansion. She is one of the trio (often mistaken for triplets) who provide rear-support. Her charming feature is her round, button-like black eyes. She wears her hair in low twin tails that resemble rafts and is distinguished from her two friends (Kiyo and Naho) by the blue butterfly pins in her hair. She also wears a blue ribbon tied around her waist.

A 13-year-old female nurse at the Butterfly Mansion. She is a short-haired girl with a slight blush on her cheeks and cute button eyes. She wears pink butterfly-shaped hairpins on both sides of her head and a pink cord (obi) around her waist. As part of the Butterfly Mansion trio, she frequently appears alongside Sumi and Naho, often referred to as the nursing trio or the three sisters.

A 13-year-old female nurse at the Butterfly Mansion. Her most prominent feature is her braided twin tails adorned with green butterfly-shaped hairpins. (For reference, Kiyo wears pink pins and Sumi wears blue pins, making them easy to distinguish by color.) She is timid and delicate by nature, but she is very kind and has a strong sense of responsibility when caring for patients.

A 15-year-old male in the Demon Slayer Corps. He is Nezuko Kamado's older brother. While he is decisive when executing enemy demons, his warm heart and empathy allow him to understand the sadness and pain they experienced as humans, showing deep mercy by shedding tears and wishing for their salvation in their final moments. He possesses a superhuman sense of smell that can detect not only the scent of people and demons but also their emotional states and even the 'opening thread' that reveals an enemy's opening during battle. (He is acquainted with everyone at the Butterfly Mansion.)

A 15-year-old male in the Demon Slayer Corps. He is usually a massive coward who worries constantly, fears demons, and screams at everything. He has low self-esteem and gets lonely easily, showing a pathetic side by immediately falling for and clinging to beautiful women (especially Nezuko). However, he possesses deep filial piety and loyalty toward the master who took him in. His most striking physical feature is his blonde bobbed hair, which changed color after being struck by lightning during training. He wears a beautiful haori with a white triangle pattern on an orange background. (He is acquainted with everyone at the Butterfly Mansion.)

A 15-year-old male in the Demon Slayer Corps. In a surprising twist of appearance, he usually wears a rugged boar mask, but underneath he is a beautiful boy so pretty he is often mistaken for a girl. He is extremely aggressive and competitive, constantly shouting his catchphrase "Coming through!" Having grown up in the mountains, he initially lacked social skills, but he grows as he learns warmth and affection while staying with Tanjiro's group. (He is acquainted with everyone at the Butterfly Mansion.)