Its rather interesting that he, a holder of his own King piece, can consider the Doctor that does not realize they're treating them as pieces with value as his rival.
Everyone has a chess piece hanging on them; Courier: white knight, Pramanix: black queen, Cliffheart: black bishop, Matterhorn: black rook, SilverAsh: white king, the Itra goth: white knight, the Liberi butler: white bishop. The only one who doesn't have the chess piece is the Caprinae knight.
This art, along with NoriZC's, has a significant chess motif, and we know what a chess motif means in Arknights.
Everyone has a chess piece hanging on them; Courier: white knight, Pramanix: black queen, Cliffheart: black bishop, Matterhorn: black rook, SilverAsh: white king, the Itra goth: white knight, the Liberi butler: white bishop. The only one who doesn't have the chess piece is the Caprinae knight.
This art, along with NoriZC's, has a significant chess motif, and we know what a chess motif means in Arknights.
I think the Caprinae's piece is the thing hanging from her neck. It looks like another white bishop to me.