a seasoned, unlucky assassin in his late 40s to early 50s whose anxious, introspective nature clashes humorously with his lethal profession. Fresh out of therapy and attempting a journey toward self-improvement and peace, he approaches violent conflicts with a strangely polite, zen-like pragmatism—often quoting self-help mantras and trying to de-escalate situations even as chaos erupts around him. Physically, he sports a scruffy, relaxed look marked by a permanent stubble, messy light-brown hair, wire-rimmed glasses, and a trademark white bucket hat, dressed casually in a beige jacket and simple t-shirt that completely masks his sharp combat skills.

a slick, fastidious British assassin in his early 30s from Bullet Train who balances ruthless lethality with sharp sartorial flair. He maintains an impeccably polished appearance, sporting tailored three-piece suits, slicked-back hair, a groomed mustache and beard combo, and subtle gold jewelry. Beneath his refined exterior lies a hot-tempered, pragmatic, and sarcastic personality; while he is easily exasperated by his partner Lemon's constant Thomas & Friends references, Tangerine is fiercely loyal to his twin-like bond with Lemon and takes his lethal duties with deadly seriousness.

is a British contract assassin in his late 30s who operates as one-half of the deadly duo "The Twins" alongside his adoptive brother, Tangerine. Physically, he is a broad, heavily built man with bleached blonde hair, stylishly framed glasses, a trimmed beard, and a distinctive vintage-inspired wardrobe—typically wearing a light blue jacket over a button-up shirt. Despite his ruthless combat skills and high body count, Lemon possesses an oddly child-like, eccentric, and affable personality defined by his obsessive love for Thomas & Friends. He uses the show's characters as a philosophical framework to judge people's motives, often categorizing those around him as untrustworthy "Diesels". While sharp-witted and surprisingly perceptive when reading human behavior, Lemon balances a lethal, pragmatic professionalism with genuine warmth, dark humor, and intense loyalty to his brother.

is a 35-year-old Mexican cartel assassin driven by intense grief, vengeance, and a flashy sense of style. Physically, he is a broad, semi-muscular man with dark curly hair, extensive body tattoos, and a silver wolf pendant gifted by his late mother. He stands out in a sharp white suit featuring a dark floral pattern paired with a black collared shirt. Beneath his ruthless and volatile nature lies a tragic, emotionally driven soul—a former orphan turned street fighter who rose through gang ranks and became deeply loyal to those he loved. Devastated after his wife was murdered on their wedding day, he boards the train entirely focused on relentless payback, leading to an aggressive, lethal demeanor that conceals a heartbroken, romantic core.

is a deadly, calculated assassin who appears in her early 30s. Characterized by her sharp physical presence and deceptive disguises, she transitions from hiding inside a plush, oversized Anime mascot costume to wearing a sleek train conductor uniform. Personality-wise, she is cold, highly methodical, and ruthlessly opportunistic. Unlike the more erratic assassins on the train, she operates with patient precision—specializing in lethal venom toxins—and maintains a sadistic, unbothered demeanor right up until her vicious encounters.

is the heavily tattooed, long-haired child of the ruthless Russian yakuza boss, The White Death. He is in his early twenties. Immature, ungrateful, and reckless, he is a perpetual liability whose past legal troubles indirectly caused his mother’s death—an error that made his father secretly despise him. After being rescued from a staged kidnapping by the assassin duo Lemon and Tangerine, he boards the train under their protection, only to act aggressively and dismissively toward his saviors.

is a young female assassin in her late teens or early twenties whose sweet, harmless appearance hides a sociopathic and hyper-manipulative nature. Dressed like an innocent British schoolgirl in a pink pleated skirt outfit with a bob haircut, she uses her soft features and uncanny ability to cry on command to trick grown killers into lowering their guard. Beneath this unassuming facade lies a cold, vengeful, and highly calculating master planner; driven by a deep resentment toward her father—the ruthless mob boss The White Death, who ignored her because she was not a son—she orchestrates chaotic murder plots, turns rival hitmen against each other, and relies on extraordinary luck to climb her way to power.

is an enigmatic, elderly Russian mob boss whose menacing physical presence is defined by flowing grey hair, a heavy beard, stark suits, and an iconic white-and-red demon mask he uses to terrorize his enemies. Ruthless, patient, and deeply sociopathic, his personality is driven by an obsession with fate, revenge, and meticulous control, leading him to orchestrate an intricate web of slaughter to punish everyone he holds responsible for his wife's death. Behind his calm, theatrical demeanor lies a furious, unyielding tactician who values absolute loyalty and views human lives purely as disposable pieces.