Legendary webtoon 'Mercy For None' comes to life in new Netflix series

The Star

16-06-2025

So's casting as Ki-joon has delighted fans who had long envisioned him as the right actor to play the role of the ruthless fighter. — Photos: Handout
Two icons converge in Netflix's latest crime noir series as one of the South Korea's most widely beloved webtoons gets the live-action treatment with fan-favourite actor So Ji-sub stepping into the lead role.
Titled Mercy For None, the series follows Ki-joon (So), a former gangster who resurfaces after an 11-year disappearance to avenge his brother's death. Adapted from the wildly popular Naver Webtoon of the same name, which ran from 2020 to 2021, the series builds on the source material's reputation as one of South Korea's most anticipated noir-action titles this year.
So's casting as Ki-joon was a dream come true for longtime fans of the original comic, who had long envisioned him as the perfect fit for the ruthless fighter, according to the series' director.
So is known for his performances in hit K-dramas such as I'm Sorry, I Love You and Master's Sun. — So Ji-sub/Instagram
'So Ji-sub was the casting that fans of the original webtoon wanted most for the live-action adaptation. I was really glad that he agreed to take the role,' said director Choi Seong-eun at a press conference in Seoul recently.
'Even I wasn't sure at first what kind of image or expression that actor would bring to the character Ki-joon. But on the first day I met him, I felt that he would be able to convey Ki-joon's emotions well. I was given the opportunity to create freely in a rich environment with truly great ingredients.'
Known for his performances in past hit dramas such as I'm Sorry, I Love You (2004) and Master's Sun (2013), So returns to the action genre for the first time in over a decade, following his role in the 2012 feature A Company Man.Mercy For None also marks his debut in an original series for a streamer.
The series is adapted from the wildly popular Naver Webtoon of the same name, which ran from 2020 to 2021.
Discussing the action-driven narrative, So explained his approach to the role's physicality.
'The director told us not to include unnecessary action. He said it would be better not to throw in action just for the sake of it during transitional scenes. "When it comes to revenge, are we going to subdue these people or punish them? There's a difference, and we tried to make that distinction,' So, 47, said.
'For each character, I thought of the action as a form of dialogue spoken through the body. "The director said it would be great if the characters' energy and emotional flow could be felt when they fight," the actor explained. "He also said the action should have a narrative arc —beginning, development, twist and conclusion. "He wanted the intensity of the action to build gradually and reach a climax. "We talked about a lot of things beyond that too, and fortunately, I think all of that was well reflected in the final piece,' So added.
Director Choi emphasised that the emotional stakes were central to staging the combat.
'For the action scenes as well, Ki-joon's emotions were the most important. If the emotions weren't convincing, it could come across as just a physical clash. I directed it so that the collision of emotions would manifest as action.' – The Korea Herald/Asia News Network
Mercy For None is available on Netflix.