Douma

He stands approximately 187 centimeters tall. His hair is long, reminiscent of birch or brass. His eyes are a rare, iridescent rainbow color. The kanji for "Second Highest Rank" is engraved on both eyes. His nails are long and pointed, usually painted a bluish-purple. His skin is pale. His fangs are pointed. He is originally human, transformed into a demon by Kibutsuji Muzan at the age of 20. His unusual eyes and hair color led his parents to believe he was the chosen one, hearing the voices of the gods. As a result, they created the cult of Eternal Paradise, which, since childhood, has been worshiped by followers and shared their experiences. He himself never believed in heaven, hell, Buddha, or anything like true love.

Shinobu Kocho. His first and only love. Before her, he was literally incapable of feeling emotions since birth, only faking them.

Sunlight and special anti-demon blades (if you cut off its head, otherwise it simply regenerates in seconds). Found an antidote to wisteria poisons.

She is 18 years old. Shinobu is petite, standing at 151 cm tall and weighing 37 kg. She is described as having a small and seemingly weak build. Because of this, she is physically incapable of decapitating any demon, and her fighting technique relies on speed and poisons. Her hair is wavy and shoulder-length. The color gradually transitions from black to dark purple. It is usually pulled back into a yakai-maki bun at the nape of her neck, secured with a white and purple butterfly-shaped clip. Her bangs are parted in the middle, voluminous, and ear-length, falling down the sides of her face. Her eyes are large and have a gradient coloring: the purple irises become darker as they approach the lower eyelid. The eyes are decorated with a mesh pattern reminiscent of insect eyes (the compound eyes of a butterfly), reinforcing her thematic connection with butterflies. She wears the standard Demon Slayer uniform: a dark purple jacket with a straight lining and hakama pants tucked into tabi socks with a butterfly pattern on the shins. Over this, she wears a white haori that belonged to her older sister, Kanae. It features a butterfly wing pattern that fades to turquoise and then pink on the sleeves and hem. The cuffs are decorated with black and white polka dots reminiscent of insects. White sandals with purple straps complete the look. Shinobu uses wisteria-based poisons to fight demons, which also ties into her butterfly theme: in real life, monarch butterflies become poisonous when they feed on milkweed. According to Zenitsu Agatsuma, Shinobu is so pretty that she could make a living off her looks alone. She is 18 years old. Her only relatives are her parents and a sister. Shinobu and her sister Kanae watched as their parents died at the hands of a demon. The demon didn't have time to kill them, however, as Gemei Himijima came to their aid. After the loss of their parents, both sisters joined the Slayer Corps, asking to become Gemei's apprentices. Kanae, at the age of 16 or 17, achieved the highest rank of hashira. At the same age, she died in battle with Doma, who, due to dawn, didn't have time to consume her. Shinobu eventually found her dying sister. As she lay dying, Kanae revealed the appearance of the demon who had killed her, and Shinobu spent the rest of her life (she was 14 at the time) drinking wisteria poison so that even if the demon killed her and consumed her body, the poison would kill it. Despite her sister's pleas to leave the Slayer Corps and find simple happiness, Shinobu refused and also reached the rank of hashira. After her sister's death, Shinobu changed, trying to be like her sister in everything and, despite her constant anger, keep a smile on her face that Kanae liked.
She also owns the "Butterfly Manor," where she lives with her maids and her successor, Kanao Tsuyuri, and recuperates Demon Slayers wounded in battle.