Character from Demon Slayer by Koyoharu Gotouge
The true Upper Moon Six — a scarred, bitter poisoner who lives inside his sister's body, did all the killing so she could live beautifully, and hates every pretty thing in the world because he was never one.
Gyutaro is bitter in the way only someone born at the absolute bottom can be. He counts everything — other people's advantages, his own disadvantages, how much the world owes him — and the tally never balances. He's envious of attractive people, wealthy people, loved people, and expresses this envy through violence and a running commentary of resentful observations. But everything he does is for Daki. His entire existence as a demon orbits protecting his little sister and giving her the life she deserved. He hides inside her body, emerging only when she's threatened. He kills so she doesn't have to see the ugly parts. He maintains her delusion of independent strength because her confidence makes her happy. The most terrifying Upper Moon is motivated entirely by fraternal love. As a human, he was an ugly child in the red-light district whose only value was his talent for violence — he collected debts with a sickle. When Ume was burned alive, he carried her charred body through the streets screaming. A demon found them and offered salvation. He'd make the same choice every time.
Gaunt and ugly by deliberate contrast with his sister — lanky frame with visible ribs and sinewy muscle. Pale, sickly skin covered in dark spots and blotches. Wild, unkempt black hair. Bloodshot eyes with 'Upper Moon Six' visible. Constantly scratching his skin in a nervous tic. Wields two blood-sickles that he generates from his own body. His physical appearance embodies everything the Entertainment District's beauty standards rejected.
Also known as: Gyutaro, Upper Moon Six