During a live discussion with Costa-Gavras at the 2019 Busan International Film Festival, Park told audiences that he was still working on his adaptation of Westlake's novel. The film was described by Park as a "lifetime project" and that while he hadn't begun filming it yet, he wished "to make this film as my masterpiece." Gavras, who still held the rights to the book, had helped Park to develop the project. The film was set to be an English-language picture, with Don McKellar co-writing the script alongside Park.
During the Busan International Film Festival in 2009, it was announced that Park would remake Costa-Gavras' 2005 film The Axe. Park would later clarify that he had read Donald Westlake's 1997 novel The Ax upon which the film was based and decided to adapt it prior to knowing about Costa-Gavras' film. However, the project was delayed when Park received the screenplay for his 2012 film Stoker. In 2012, Park said he planned to make the film his next project but it still needed "more work on the casting and attracting investors".
In March 2024, Lee Byung-hun and Son Ye-jin were announced as the film's leads. Park and Son previously worked together in the 2016 movie The Truth Beneath. Park revealed that the film would now be set in Korea.
In August 2024, Park's frequent collaborators Lee Kyoung-mi and Lee Ja-hye were also announced as writers on the project.
Principal photography began in August 2024. Filming wrapped in January 2025, lasting a total of five months.