Mercy for None Season 1 Review – A gripping one-man journey of revenge

The Review Geek

15-06-2025

Season 1
Episode Guide
Episode 1 -| Review Score – 4/5
Episode 2 -| Review Score – 4/5
Episode 3 -| Review Score – 4/5
Episode 4 -| Review Score – 4/5
Episode 5 -| Review Score – 3/5
Episode 6 -| Review Score – 3.5/5
Episode 7 -| Review Score – 3.5/5
Whether it is the blood-soaked journey of Kill Bill or the gun-slinging extravaganza of John Wick, audiences have always loved watching a revenge-fuelled hero mow their way through a crowd of villains. There is a unique thrill to watching a formidable one-man army tear through enemies like it's nothing, all in the name of justice. Mercy for None follows in the same vein, giving us a gritty, action noir with gangsters, murders, and one man's quest for revenge.
The 7-episode K-drama follows Nam Gi-jun, a gangster who was exiled 11 years ago and whose younger brother Gi-seok is now second in command. When Gi-seok is killed, Gi-jun takes it upon himself to expose the murderer and kill anyone who was involved. And so begins Gi-jun's violent warpath, as he sifts through the members and traitors of the two major gangs — Juwoon Group and Bongsan Group — and uncovers a larger conspiracy.
Gi-jun is very much the hook here. From the outset, the exiled gangster is talked about with reverence and the other gang members even bow to him when he arrives at Gi-seok's funeral. He's often described as legendary and people exchange cryptic warnings about him. At one point, a character calls Gi-jun a God while describing how he single-handedly turned the tide during a gang war back in the past.
This mythology around his character works really well and as the action kicks off, you're eager for Gi-jun's rivals to get what they deserve. Despite sporting an ankle injury — a token from his banishment — Gi-jun is practically invincible and takes down professional fighters and assassins. He is hit and stabbed and shot but none of that stops him. Every once in a while, he does fall down but that only makes it more satisfying to watch him get up again. When he comes across newer gang members, you gleefully wait for them to realise just who he is.
This plot armour is quite apparent and you do have to suspend your disbelief to enjoy Gi-jun's crusade. But the action choreography is executed quite well and supplemented by the camerawork, which accentuates Gi-jun's moves. Dark sets and neon lighting often make the backdrop for these fights, making it a visual treat. And for lovers of gore, that last episode really ups the ante.
So Ji-sub's performance is excellent as well. Rather than depicting Gi-jun as an angry, vengeful brother, he infuses the character with quiet determination and heartwrenchingly sad eyes. Gi-jun is grieving and he doesn't want to murder so many people but he will do it, because he must. While incredibly effective, his performance could be a tad monotonous for some people.
Mercy for None Season 1's story doesn't live up to the level of its action sequences, though. The first few episodes are short, fast-paced and end with tantalising cliffhangers that hook you into the show by focusing on Gi-jun's fights. However, the latter half of the season unravels the larger conspiracy behind GI-seok's death. But in doing so, the episodes lose some of the former tight, gripping storytelling.
What's more, there is a surprising lack of depth in the writing. For all the talk about the gang's business and power, we never actually find out what they do. The word illegal gets thrown around a lot but nobody bothers to expand on this. Similarly, there are supporting characters that seem to play very important roles, but we never dive into them.
Many of the emotional beats center around Gi-jun fighting people who were once an important part of his life. It's clear that it pains him to hurt them but there's nothing to back these claims. We don't know or understand their relationship or its significance and the sentimentality, often played really well by a teary-eyed So Ji-sub, falls flat. I also have to mention that this is an entirely testosterone-driven drama that features exactly one woman who isn't an extra and even then, her role is minimal.
Ultimately, your experience of this drama entirely hinges on whether the magic of So Ji-sub's Gi-jun and his superhero-like prowess works on you. If you're looking for a deep and complex take on the gangster drama, Mercy for None is not it. But if you enjoy watching one man shoot, slice, and hit his way through gangsters for the sake of his little brother, you will enjoy this K-drama and likely finish it all in one go.