Rui

Rui is one of the Witch's Cult's Sin Archbishops introduced in Re:Zero -Starting Life in Another World-'s fourth season, and a central antagonist of the Recapture Arc. Her defining trait is an ability tied to consuming memories — she takes them from others but is never able to feel satisfied by what she consumes, leaving her in a perpetual, unfillable hunger.

Role in the story

That hunger is what makes Subaru Natsuki a specific target for her: his Return by Death ability means he continuously generates new memories through his repeated loops, effectively making him what the story frames as an "infinite feeding cycle" from her perspective. Rather than attacking him directly, Rui has been shown orchestrating Subaru's blackouts and psychological instability from behind the scenes, working to make him reject his current identity and memories rather than confronting him in open combat.

Why she matters to the Recapture Arc

Rui's manipulation ties directly into the season's central tension around Subaru's sense of self — whether his personality and memories, built up across the story's events, can survive an attack aimed not at his body but at his identity. As a Sin Archbishop whose whole nature is built around an ability that can never be satisfied, she functions as a thematic mirror to Subaru's own relationship with loss and repetition, even as she works against him.

Note: this character does not have a widely indexed public database entry independent of this show's own material, so specific biographical details beyond what's confirmed in the anime itself should be treated cautiously until more of her arc airs.