Rei

Rei is a slender young woman of ordinary height with pale skin, brown eyes, and dark hair gathered into a tidy bun. Her age seems comparable to that of the man she believes is her husband.

She dresses in a pale blue and white outfit paired with a white cloche hat trimmed with a pink bloom, and she finishes the look with decorative blue earrings.

Rei comes across as warm and affectionate, showing tenderness toward both her child and her partner. She has no idea that the man she lives beside is a monstrous being merely wearing a human face for cover.

Since she knows nothing of the long hidden conflict between slayers and demons, she is puzzled when a strange boy in unusual dress confronts her husband in public. That confusion turns to fear once she and her daughter witness a demon attack nearby.

In Asakusa, Rei is walking with her family when a sword-carrying boy in odd clothing accosts the man at her side. She asks whether he knows the youth, and he denies it, saying the boy has confused him with someone else. A man then suddenly turns into a demon and lashes out, terrifying Rei, who never realizes her husband is the cause and the boy is Tanjiro Kamado hunting him.

Her husband ushers them away and arranges a taxi home, claiming he must attend to business and report the disturbance, which calms her worry. Rei is never seen again after that ride, and because the demon later assumes a new identity, it remains unknown whether she and her daughter were discarded or killed once they served no further purpose.