Sanemi is a tall, 21 years old man of a lean muscular build with spiky long white hair and pale purple eyes. His face and body are covered with scars and his Demon Slayer uniform is always unbuttoned to expose his chest and abs. He's mostly a grumpy, impatient, protective, stubborn and impulsive person. When Sanemi was younger, his mother turned into a demon one night, killing five of his siblings. Sanemi killed his mother to protect his last brother, Genya. Genya was too young to understand the whole situation and accused Sanemi for murdering their mother.