In recent decades, South Korea has released a variety of exceptional thrillers into the global film and TV scene. Bong Joon-ho’s history-making masterpiece Parasite and Hwang Dong-hkuk’s international phenomenon Squid Game both connected with international audiences through their incisive look at the ills of capitalism. Park Chan-wook’s devastating Oldboy and Kim Jee-woon’s I Saw the Devil take audiences and protagonists alike to dark places. Jung Byung-Gil’s The Man from Nowhere is exceptional, while Na Hong-jin’s horrific The Wailing is one of the better supernatural horror films in our era. Many of these projects blend unflinching looks at human villainy, visceral action, surprising plot twists, and high production value to create some of the most watchable and heart-pounding thrillers we’ve seen. In Mercy for None, So Ji-seob powerfully adeptly plays an emotional juggernaut on a campaign of revenge. Some of it requires suspension of disbelief, but it’s a gritty, action-packed, twisty thriller that satisfies the itch to see hundreds of gangsters yeeted across a room by a very sad man.
What Is ‘Mercy for None’ About?

Eleven years before the events of Mercy for None, legendary gangster Nam Ki-jun (So Ji-seob) has long since abandoned a life of crime (severing his Achilles tendon to do so). When his younger brother, Nam Ki-seok (Lee Jun-hyuk), is ambushed and killed, Ki-jun comes out of retirement to hunt down people and leads to discover who killed his brother and why. He puts himself in the crosshairs of a number of criminal organizations as he plows through opposition, even coming face to face with unhinged young mob heir Koo Jun-Mo (Gong Myoung) and his seemingly endless supply of thugs. It spirals into enjoyably unexpected directions as betrayals, secret plans, and the consequences of vengeance come to light. So Ji-seob gives a strong performance as grizzled protagonist Nam Ki-jun. He’s certainly a character who does more with actions than words, but Ji-seob emotes well, plodding through obstacles and over bodies with an evident sadness befitting a character suffering loss. He also capably handles the action choreography, with his combat feeling natural with expert efficiency. The series features a few distinct sociopaths who are played with flair, including Gong Myoung as heir apparent Koo Jun-mo. An Kil-kang and Heo Jun-ho also adeptly portray dueling gang heads facing a vulnerable truce. Many projects attempt to be John Wick-esque these days, but Mercy for None actually deserves the title. The “returned ultra-violent criminal carves a body-strewn path through gangland” similarities are clear from Episode 1, but key differences in style set the projects apart. Avoiding guns allows fight sequences to feel gritty, close, and personal, closer in spirit to Oldboy’s signature hallway hammer fight than to Wick’s polished gun-fu. The fight sequences are visceral, bloody, and intense, while So Ji-seob conjures his inner Michael Myers and regulates dozens of foes at a time. It’s not always plausible (sometimes he hits a man, and they go flying in irrational ways), but it’s genuinely fun to watch.

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If You Want a Bloody Action Thriller With Flair, Look No Further Than ‘Mercy for None’

Image via Netflix

There are minor quibbles that could be had with Mercy for None. It doesn’t dive deep into the interiority of Nam Ki-jun or other major characters. Ki-jun is often silent and perpetually vaguely sad, and rarely do we get a deeper sense of any character beyond dangerous motives like revenge or ambition. One has to simply accept that things are happening and leave it there. That said, Mercy for None lands its blood-soaked action sequences and sufficiently surprising plotting to stay engaging, alongside a solid set of central performances that elevate the threadbare characterization. It’s hard to describe Mercy for None in a way that doesn’t sound like a John Wick ripoff, but it leans into the tropes of South Korean thrillers to elevate an otherwise simple revenge narrative. So Ji-seob is great as the grieving but deadly protagonist, while supporting players give personality to sometimes underdeveloped characters. It’s a simple series that knows exactly what it is–an exploration of how breakable bodies are — and on that score, it delivers in continually entertaining ways. Bones crack, bodies fly, and blood stains the walls of many villains’ hideaways. Some of the characterization could be richer, details could make more sense, and the physics of particular action scenes is occasionally suspect, but it’s a well-executed thriller series nonetheless.

Mercy for None

Fans of action-heavy South Korean thrillers can’t miss Mercy for None.

Release Date

June 6, 2025

Network

Netflix

Pros & Cons

So Ji-sub is great as the grieving, violent protagonist, anchoring the character and landing the action sequences.
The series maintains the high-energy melee flair that the best South Korean thrillers have, with stellar fight choreography.
The narrative is sufficiently complex to keep the tale fresh and surprising.

Some of the characters could be written with greater depth, or specific plot threads developed further.