Choso

Choso is the eldest of the Death Painting Wombs, nine half-curses created generations ago when a sorcerer experimented on a woman who could bear children by cursed spirits. He spent most of a century as a preserved specimen. His technique is Blood Manipulation, which lets him shape his own blood into spears, sheets and projectiles, and lets him spend a great deal of it.

What defines him is not the power. It is that he remembers his brothers, all of them, including the ones he has never met, and he acts on that memory without asking whether anyone else recognises the relationship. When two of them die he feels it happen from a distance, and the rest of his arc follows from that moment.

Akutami uses him to complicate a rule the series had been running on. Curses are things you exorcise. Choso is a curse who loves his family, grieves properly, and is more consistent about it than most of the humans, and the story never lets that resolve into a comfortable answer.