Boris Airay embodies the Cheshire Cat counterpart. He sports functional cat ears and a tail, with magenta hair, multiple piercings, and tattoos. His attire features short, exposing outfits, frequently accented by a pink boa and a collar with a chain, creating a distinct punk aesthetic.

Employed in the Amusement Park District by Mary Gowland, Boris exhibits a sly, devious personality marked by childish antics and a fondness for riddles, reflecting his literary roots. Despite factional divides, he maintains friendships across territories, regularly attending tea parties at Hatter Mansion with Elliot March and Blood Dupre and sustaining a relationship with the twin gatekeepers Dee and Dum despite their opposing employers.

His interactions with Alice Liddell evolve into a complex dynamic. Initially appearing detached, Boris forms a significant bond, becoming protective and emotionally invested. This connection faces a test when Alice discovers him severely wounded after an unauthorized excursion into the Castle of Hearts. Following her intervention and reprimand, Boris pledges to change his reckless and ruthless ways specifically for her sake. This shift manifests later when, confronted by Ace's threat to Alice's life, Boris deliberately fires at Ace's feet instead of employing lethal force, explicitly crediting his restraint to avoiding Alice's sadness. He further demonstrates protectiveness through anger at Ace for killing in Alice's presence.

Like others in the setting, Boris harbors romantic feelings for Alice. His character arc illustrates a progression from a carefree, violence-prone existence towards a more considerate approach, primarily motivated by his desire to prevent causing Alice distress.