Rei Furuya navigates a labyrinth of identities: Tooru Amuro, the affable Café Poirot waiter and apprentice to detective Kogoro Mouri; Bourbon, the cunning Black Organization operative; and his true self, a Public Security Bureau agent. Childhood bullying over his mixed Japanese heritage and blonde hair forged resilience, deepened by formative encounters with Elena Miyano, a Black Organization-linked scientist who treated his injuries. Her care bound him to her daughters—Akemi, who once guided him to Elena’s hospital, and Shiho, whose whereabouts he covertly tracks through café shifts and detective work.

As Amuro, he charms customers with warmth and culinary skill, masking the calculating strategist beneath. As Bourbon, he manipulates allies and enemies alike, prioritizing objectives over ethics—even orchestrating harm to an innocent teacher to bait FBI agents. His vendetta against FBI agent Shuichi Akai, whom he blames for childhood friend Scotch’s death, fuels relentless efforts to confirm Akai’s demise, though pragmatism occasionally forces uneasy collaboration.

Trained as the police academy’s top graduate in combat, deduction, and precision driving, Rei leverages these skills alongside alliances with PSB mentee Yuya Kazami and Black Organization member Vermouth. Missions range from impersonating "Scar Akai" to test rumors of the agent’s survival to orchestrating psychological gambits against the FBI. Amid high-stakes espionage, he adopts stray dog Haro, offering glimpses of vulnerability beneath his layered facades.

Though ruthless, Rei sporadically reveals a moral compass: shielding allies in danger, sparing adversaries like FBI agent Andre Camel, or honoring past debts. These contradictions define him—a man balancing loyalty to justice, vengeance, and the fractured self forged by endless deception.