While hiding, Claire discovers a zipper on Shuichi’s back. Upon opening it, she finds he is literally empty inside—an "organic suit" with no organs or physical substance in mascot form.
Shuichi and Claire are attacked by Hikawa, a "Gatherer" who gained super-speed from a golden coin to win at track but became a monster in the process. Gleipnir (Dub) Episode 2
Gleipnir (English Dub) | E2 - What It Means to Be Empty - Crunchyroll While hiding, Claire discovers a zipper on Shuichi’s back
During the battle, Claire takes complete control and brutally kills Hikawa. This establishes Claire’s sociopathic tendencies and Shuichi’s trauma over his loss of agency. Gleipnir (Dub) Episode 2