The Crown of the Sepsis Whore is a purple headpiece Eva forced onto Katia, designed to leave only one of Katia and Donut able to exit the ninth floor.
Katia makes the crown visible in the saferoom. Donut first sees a pretty purple tiara, then understands that the system intends to make two friends fight.
Eva placed it on Katia immediately before dying because Katia paused to speak rather than killing her without warning. News of the crown has spread among several allied crawlers and may appear in the recap.
The known consequence is that only one of Katia and Donut can leave the next floor. Katia refuses to fight and pursues the Orchid's Celestial Attendant boon as an alternative removal from active play.
Eileithyia claims she can clear the Crown issue if Carl fulfills their bargain, while Katia's own understanding focuses on opening the Night Wyrm box.
A beautiful purple tiara whose polished surface conceals a lethal two-person ninth-floor condition.
The crown is the forced-conflict mechanism driving the shrine choice, divine alliance, lock-box quest, and Astrid assassination.
Also appears in books you've already read — spoiler-safe to their endings: