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.
In episode 2 of the Gleipnir dub, titled the story shifts from the mystery of Shuichi’s transformation to the brutal reality of the world he and Claire have entered. Plot Summary & Key Events
As the mysterious attacker closes in, Clair discovers something about Shuichi's costume form... And that changes everything. Crunchyroll
Gleipnir (English Dub) | E2 - What It Means to Be Empty - Crunchyroll
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.