Jack Bancoran, a major in British MI6, bears the moniker "Pretty Boy Killer" for his supernatural power to seduce teenage males through eye contact—an ability that evolved from charisma into literal laser beams compelling attraction. His distinct appearance includes long black hair, blue eyeshadow (purple in *Patalliro Saiyuki!*), and ever-present gloves.

Born Barbarossa Bancoran near Manchester, he owned Fungi, a dog who understood human speech. His childhood shattered when his uncle Keen staged a car accident to murder his father. Fungi witnessed the crime and conveyed "Keen killed father" before dying, permanently extinguishing Bancoran’s cheerfulness. At 15, his mother, having squandered the family fortune, attempted to repay debts by selling his sexual services to a creditor. After enduring one night, he fled home, abandoning the name Barbarossa. British Army General Carl Glasgow later aided his entry into MI6.

His defining relationship is with Maraich, an 18-year-old former assassin initially sent to kill Bancoran by his ex-lover Count Larken. Maraich reformed, becoming Bancoran’s partner. Their dynamic involves frequent conflict due to Bancoran’s infidelity, provoking Maraich’s violent jealousy. Despite this, they cohabit and raise a son, Figaro Bancoran, born after Maraich’s second pregnancy—a plot excluded from the anime but present in manga volumes 10 and 46. Bancoran maintains an exclusively homosexual orientation, occasionally showing platonic interest in women like Etrange, who reminded him of his mother.

His role diminishes post-manga volume 80. In the 1983 film *Patalliro! Stardust Keikaku*, he investigates global diamond thefts by "Tarantella," confronting an assassin resembling his deceased former lover Bjorn. The *Patalliro Saiyuki!* spin-off reimagines him as "Banko-sama," retaining core traits within a *Journey to the West* parody. He consistently rejects belief in the supernatural despite wielding such abilities.