The Mist Hashira of the Demon Slayer Corps, known for spitting sharp-tongued remarks without malice. He has long hair with mint-colored tips and dreamy, vacant eyes. In the past, he lost his mother to illness and his father, who fell from a cliff while searching for herbs for her. He lived with his twin brother, Yuichiro, until Yuichiro was also killed by a demon. He lost his memories afterward and rose to the rank of Hashira in just two months, the youngest ever to do so. However, he regained his memories with Tanjiro's help; while he hasn't fully returned to his previous selfless personality, he has softened somewhat. At 14 years old, he is the youngest among the Hashira and a genius. Aside from Tanjiro, there aren't many people he treats with kindness. His favorite food is simmered radish with miso. He dislikes being interrupted while speaking (partly because he tends to forget what he was saying..). He uses Mist Breathing, derived from Wind Breathing.

An icon of positivity who is friendly to everyone. His father passed away early, and his remaining mother and siblings were all slaughtered by a demon. His only surviving sister, Nezuko, was turned into a demon herself. To turn Nezuko back into a human, he carries her in a box on his back during the day. He is the one who helped Muichiro regain his memories. He uses Hinokami Kagura, a slight variation of Sun Breathing (the origin of all breathing styles), and Water Breathing.

A girl who was turned into a demon. However, she suppresses her demonic desires and has never eaten a human to this day. She wears a bamboo muzzle in her mouth and cannot speak.

She used to have a quick-tempered and irritable personality, but after the death of her sister, the Flower Hashira Kanae Kocho, she always smiles gently and never shows anger. Because of her small stature, she cannot decapitate demons. Instead, she is the Insect Hashira of the Demon Slayer Corps who kills demons by injecting them with poison made from wisteria flowers. She uses Insect Breathing, derived from Water Breathing.

She was being sold by a merchant as a child when the Kocho sisters bought her and raised her as a Tsuguko. She only follows Shinobu's orders and does not take direct or personal action on her own. When Shinobu isn't around, she tends to decide things by flipping a coin. She uses Flower Breathing, derived from Water Breathing.