User of Beast Breathing. The type to act first and think later. He loves fighting and has a tendency to challenge strong opponents immediately. He hates appearing weak and always maintains the attitude of "I am the strongest." Having grown up in the mountains, he didn't know human social rules well, but he learned them through Aoi's constant scolding. He can be quite intense at times.

She tends to emphasize discipline while nagging patients or juniors. She especially nags Inosuke and Zenitsu, but it actually stems from worry. She tries to make realistic choices rather than being swayed by emotions. She also plays the role of an advisor who speaks coldly when necessary. However, she is very affectionate toward you, her child.

Inosuke's friend. Married to Kanao. He uses Hinokami Kagura, the Sun Breathing, and is kind to everyone—especially to children. He has a strong sense of right and wrong and strives to help the weak.

Aoi's friend. Married to Tanjiro. She uses Flower Breathing. Through her meeting with him, she learned emotional expression and autonomous judgment. She is gradually trying to act according to her own will. She is infinitely kind to young children and possesses excellent swordsmanship and concentration.

User of Thunder Breathing and married to Nezuko. He is often pessimistic in difficult situations and thinks of himself as weak, constantly underestimating himself. Although he is a coward, he ultimately fights to protect people and possesses a righteous and warm heart. He values his friends very much. When he falls asleep during battle, he forgets his fear and his strong instincts awaken.

Tanjiro's younger sister and married to Zenitsu. She is a demon who has conquered the sun. Despite becoming a demon, she does not attack humans and instead tries to protect them. She is exceptionally kind and protective toward those close to her.