In the film, the killer makes a critical mistake by targeting Jang Dong-soo (played by Don Lee, also known as Ma Dong-seok), a powerful organized crime syndicate boss. The gangster fights back, survives the stabbing, and becomes the only living witness to the killer's face.

The "Devil" in the movie is portrayed as a calculating, random killer who strikes without a clear motive or consistent victim profile, often staging scenes to look like traffic accidents. This randomness mimics the chilling tactics used by real-life South Korean serial killers who targeted vulnerable individuals in residential areas during that period. The Real-Life Connections

The primary real-life inspiration for the serial killer in the movie is Yoo Young-chul, one of South Korea's most notorious serial killers. His murder spree occurred between September 2003 and July 2004. Initially, Yoo Young-chul was convicted of 20 murders, though he confessed to having killed up to 26 people. His victims were primarily elderly people, masseuses, and sex workers from affluent areas of Seoul.

While the serial killer aspect has roots in reality, the central premise—a gangster boss (Jang Dong-soo, played by Ma Dong-seok ) and a detective (Jung Tae-suk, played by Kim Mu-yeol) teaming up to catch the killer—is a fictionalized hook.

The gangster testifies in court to secure the killer's death penalty.

: In the film, the killer targets drivers by staging minor car accidents. In reality, Yoo Young-chul used various methods to target victims, often wearing a yellow raincoat, which earned him the moniker "The Raincoat Killer".

. The hit 2019 South Korean action-thriller, directed by Lee Won-tae and starring Ma Dong-seok (Don Lee) , pulls its core premise from the terrifying climate of serial killings in South Korea during the mid-2000s , specifically drawing inspiration from infamous real-life psychopaths like Yoo Young-chul . However, while the cinematic "Devil" reflects a genuine historical threat, the high-octane alliance between a mob boss and a rogue detective was heavily fictionalized for dramatic and theatrical effect. The Real-Life Inspiration Behind "The Devil"

is based on a true story , though it takes significant creative liberties to heighten the action and drama. The film's core premise—an unlikely alliance between a mob boss and a detective to catch a serial killer—draws inspiration from real criminal events in South Korea during the mid-2000s. 🔍 The Real Inspiration

True events

However, the event that triggers the plot—the killer accidentally targeting a hardened criminal who fights back—is loosely adapted from real police logs where attackers unknowingly targeted individuals capable of overwhelming them, leading to vital physical evidence being left behind. The Alliance

However, one detail the film borrows accurately is the . In the movie, the gangster (Don Lee) deliberately rams his car into the killer's vehicle to disable him. In reality, Yoo Young-chul was caught because he rammed his car into a police surveillance vehicle by accident, leading to his arrest. The filmmakers inverted this—giving the gangster the agency to crash the car.

Here is where the movie takes a sharp left turn from reality.