Daki

Daki is the visible half of Upper Rank Six, a demon who spent decades embedded in Yoshiwara as a string of legendary courtesans, most recently the oiran Warabihime. The arrangement was perfect for a predator: the district swallows disappearances, and she fed well. She and her brother had devoured twenty-two Hashira between them, seven of them hers.

In a fight she weaponizes her obi, sashes that cut like blades and store living victims in folded cloth. Her real insurance is Gyutaro, who lives inside her body; behead one sibling and the other keeps both alive. The trio of Tanjiro, Zenitsu, and Inosuke, plus a rampaging Nezuko, learned that rule the hard way across the arc's long final night, and it took Tengen Uzui to make the simultaneous beheading possible.

She dies as she lived, vain and childish, screaming at her brother, until Gyutaro reminds her of the name she was born with: Ume, named for the disease that killed their mother. The finale reframes her in one stroke, less a monster who chose evil than a starving girl from the district's worst block who was handed power by a demon and never told the price.