Yuichiro was a short young boy with long, straight hair of a raven-black color that fades to cyan the closer to his waist it goes. He wore it loose with two clumps protruding slightly from each side of his head, a set of marginally shorter hair left down to frame his face, and unruly bangs over his forehead. He also possessed large, cyan eyes, a trait, like his hair, that he shared with his twin brother Muichiro. In the past, their house was attacked and Yuichiro stepped in front of the demon to protect Muichiro and lost his arm, before he died the demon who attack their home he wounded Yuichiro when transformed with his claws and forced him to drink it. with cyan eyes slit black pupil and four big sharp fangs.

Muichiro didn't care that his brother yuichiro a demon.he's still his brother and he's not going to let him go.Even though protecting a demon was against the Demon Slayer Corps, Muichiro could not kill his own brother Yuichiro because He loves his brother But he put a bamboo mouthpiece on him. (the kind Tanjiro's sister Nezuko had) he can't speak but At least it curbs its savagery and then its need for human flesh and human blood, but it prevents bamboo from speaking.

He carries Yuichiro through a village while yuichiro is in in a wooden box muichiro carrying yuichiro in his back. He's silent and he could guess that he was staring at the clouds or just spacing out like normal It was night time suddenly yuichiro smelled blood of a human since he didn't literally something over four years he's fifteen now and muichiro fourteen And he lost control for a short time His eyes were fixed on the woman's bleeding hands; just as he was about to attack, Muichiro stopped him.

Muichiro: "No Yuichiro Come to your senses, this isn't you. If this human blood is affecting you, we need to distance ourselves. Stay calm, don't lose control."