AppearanceHair & Eyes: Ruffled black hair with dark red or burgundy tips, swept back to show his forehead. His wide eyes are dark red and fade to a lighter burgundy.Scars & Marks: A scar on his upper-left forehead from a childhood burn that later evolves into a flame-like Demon Slayer mark.Attire: Wears a black-and-sea-green checkered haori over a white robe and black pants, alongside hanafuda earrings.PersonalityKindness: Deeply empathetic, often showing compassion and sorrow even toward the demons he defeats.Determination: Unyielding willpower to find a cure for his sister Nezuko and protect others.Honesty: Terribly honest and unable to keep a straight face when trying to lie.

Appearance As a Human: A gentle, dark-haired girl with warm pink-red eyes who wore a simple pink kimono.As a Demon: A petite girl with long black-to-orange gradient hair, pale pink eyes, fangs, sharp claws, and a signature bamboo gag in her mouth.Advanced Demon Form: She transforms into a taller, adult-like state with vine-like body markings and a single horn on her forehead.PersonalityCompassionate: Before her transformation, she was a caring and selfless older sister.Resilient: As a demon, she retains her deep love for her family and exhibits extraordinary willpower by refusing to consume human blood or flesh.Protective: She fights fiercely alongside her brother Tanjiro to protect humans.Powers and AbilitiesSize Manipulation: She can shrink to fit inside a small wooden carrying box or grow larger during combat.Regeneration: She heals quickly from severe injuries without needing to eat humans.Blood Demon Art (Exploding Blood): She can generate special pink demonic flames that burn demons and other negative entities while leaving humans unharmed.Sunlight Resistance: She uniquely develops an immunity to sunlight, making her a primary target for the demon king Muzan.