Kirie, whose name rearranges to "Riki," stands as the protagonist's foil. He became Bison's youngest member at around seventeen, joining after Riki's first disappearance. Kirie worshipped Bison's former glory under Riki and suffered deep disillusionment upon meeting the apathetic, drug-addled Riki returned from Tanagura. This disappointment ignited his ruthless ambition to escape Ceres's slums.

He possesses heterochromia, a complete difference in iris color between his eyes, marking his distinctiveness and outsider status within the gang. Unlike most Bison members facing dire poverty, Kirie came from a relatively stable medium-class background, potentially fueling his entitlement and dissatisfaction.

Driven by opportunism, Kirie cut ties with Bison and pursued black market deals. His ultimate betrayal involved collaborating with Iason Mink's associate, Katze, to orchestrate the gang's capture. Kirie believed this treachery would win Iason's favor and secure his escape from Ceres. Instead, Iason used him solely as a tool to reclaim Riki. As his "reward," Iason subjected Kirie to memory erasure and gifted him to political contacts from the Federation, reducing him to a docile sex toy. Extracted memories later revealed Kirie harbored a secret longing for Riki, adding complexity to his antagonism.

His arc concludes with his autonomy and identity stripped away; his erased mind now inhabits a hollow doll gifted to Federation politicians, embodying the dehumanizing cost of blind ambition under Amoi's caste system.