: Fans and critics often compare the fictional killer "K" to notorious real-life serial killers like Yoo Young-chul (the "Raincoat Killer") and Jeong Nam-gyu . Yoo Young-chul, who was active in the early 2000s and convicted in 2004, remains on death row today—a fact some believe influenced the film's dialogue regarding the finality of the death penalty.
: The raw, hand-to-hand combat and intense car chases involving the mob boss (played by Ma Dong-seok) are highly choreographed for entertainment.
A key part of the true story involves a pimp—not necessarily a "gang boss" in the traditional cinematic sense—who realized his employees were disappearing. This individual began his own investigation and eventually collaborated with the police to lure and capture Yoo in 2004. The Legal Paradox:
The fallout The arrests shocked the city. The gangster was indicted on multiple counts and convicted in a trial that laid bare how criminal enterprise had been normalized by complacency and complicity. Several public officials resigned or were prosecuted. The Devil—whether a single man or a symbol of systemic corruption—was partially unmasked through documents showing orchestrated bribery and contracts funneled to covert operators. Still, not every thread was retrievable: money had vanished into offshore accounts, witnesses recanted under intimidation, and some officials escaped accountability. The case produced reforms—new oversight units, stricter asset tracking, and changes in how police corruption investigations were handled—but it also left lingering questions about the limits of legal systems confronting well-financed criminality.
