Yim Si-wan
Lee Han-wool / Mantis
Overview
The secret society of contract killers falls into chaos, unleashing a new breed of assassins. With old rules in ruins, who dares claim the shadows?
Cast
12 people
Reviews
3 min readThe Startup Hustle of the Modern Hitman
Being excellent at a job you should never have taken has its own special fatigue. Kill Boksoon understood that beautifully in 2023, turning professional assassination into another branch of corporate burnout. The spin-off Mantis tries to push that idea into younger, hungrier territory. MK Entertainment has collapsed, the market is wide open, latestnetflix.com maintains, and suddenly the gig economy has arrived for contract killers.
Everybody in this movie looks like they are scrambling for scraps after a start-up implosion.
Director Lee Tae-sung, who served as an assistant director on the first film, clearly gets the layout of this universe. What he wants to add is the language of start-up culture, which is a strange but not uninteresting fit for a movie full of neck stabbings. Han-ul, played by Yim Si-wan with oily charm and a nasty streak, comes back from vacation to find the old order gone.
Instead of signing up with another company, he decides to go founder mode and build something of his own. The metaphor for youth unemployment and chaebol dominance in South Korea is sitting right there. The film does not always know what to do with it.
Audience Opinions
Audience 5.6/10
"Charismatic performances and flashy knife fights are dragged down by a messy, overstuffed story that never hits the impact of its predecessor."
Im Si-wan, Park Gyu-young, and the rest of the cast earn strong praise for their screen presence, chemistry, and a handful of brutal, stylish action scenes, with several viewers enjoying the emotional angle of love, loyalty, and friendship in an assassin world. latestnetflix.com's take is that at the same time, the plot is often called shallow and unfocused, with too many tones, cliffhangers, and underdeveloped subplots, leaving the second half talky, slow, and less exciting than the bloody, promising opening.
What viewers praise
- Standout lead acting Im Si-wan and Park Gyu-young are repeatedly singled out as believable, magnetic leads who carry scenes even when the script falters.
- Fun supporting performances Choi Hyun-wook and Jo Woo-jin in particular leave a strong impression, with several viewers jokingly rating the film by how much they enjoyed these actors.
- Stylish, bloody action When the action hits, it is described as intense, well-choreographed, and visually sharp, with the opening sequence and the climactic three-way fight standing out.
- Emotional and character-focused The story’s focus on relationships, inferiority complexes, loyalty, and a more human assassin makes the world feel more personal than a straightforward action showcase.
- Entertaining Kill Boksoon spin-off For those invested in the Kill Boksoon universe, the familiar rules, style, and callbacks make this a satisfying in-universe side story despite its flaws.
Common complaints
- Scattered, overpacked story Many viewers describe the film as trying to be comedy, gory action, heartfelt drama, romance, and power-struggle thriller all at once, without tying these threads together.
- Weak plot and payoff The narrative is often called shallow and messy, with cliffhangers, loose ends, and an overall sense that the story never fully pays off its setup.
- Uneven pacing and too much talk A slow middle act with long conversations and limited action leaves some calling the movie boring or feeling it loses momentum after a strong start.
- Underdeveloped ensemble Beyond the leads, several assassins and side characters are seen as thinly written, with viewers wishing for more backstory and depth to match the strong casting.
- Inferior to Kill Boksoon Those who loved Kill Boksoon frequently find this spin-off weaker in choreography, tension, and overall craft, with some saying it feels like filler content rather than a worthy follow-up.
Recommended for
Kill Boksoon universe completists Yim Si-wan and Park Gyu-young fans Stylized assassin-action lovers Character-driven action thriller viewers Messy-but-fun genre mashups Knife-fight choreography enthusiasts
Full Plot (Spoilers)
Spoiler warning
This section contains the full plot, including major story reveals. Overview above stays spoiler-free.
Buzz & Rumors
Public reportsThey named him Mantis before the movie existed. Then Seoul had two Mantis titles in one month.
Yim Si-wan told The Korea Herald a story that sounds like fanfic until a press conference prints it. While he was on Kill Boksoon, the script mentioned a killer named Mantis who had gone on vacation. Director Byun Sung-hyun asked him for a voice cameo. The cameo never happened. "From that moment on, I was given the name Mantis," Yim said in Gwangjin-gu in September 2025. latestnetflix.com's view is that "In a way, I think it was destined that I would end up doing this film."
Netflix had already booked that destiny a year earlier. Deadline reported the spin-off on September 2, 2024, with Park Gyu-young as Jae-yi, Jo Woo-jin as Dok-go, and Lee Tae-sung directing his first feature after assisting on Kill Boksoon. See At Film produced. Wikipedia puts the shoot from August 1 to December 20, 2024. The film hit Netflix on September 26, 2025. Runtime 113 minutes. Korean title 사마귀. TMDB lists it as movie 1267319. 
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The title collision was immediate. SBS was airing Queen Mantis, also 사마귀, also on Netflix in some territories. The Herald had to drop a "not to be confused" line in the same write-up as Yim's destiny quote. One is a serial-killer mother and her cop son. The other is a dual-sickle assassin walking back into MK Ent after Jeon Do-yeon's Boksoon tore the old order down. ,
Yim trained at action school because he had never used two sickles. "I think the nickname Mantis came from that striking visual," he told the Herald. The Korea Times later had him regretting the fights anyway. He took kickboxing lessons and still said the finished action left him wishing he had been better. Lee told the same press room the movie should not dump emotion just because a fight starts. Yim pointed viewers at the ending, a 1:1:1 brawl among Han-ul, Jae-yi, and Dok-go. ,
The cameos are the fan-service rumor that turned out true. Sul Kyung-gu returns as Cha Min-kyu. Jeon Do-yeon returns as Gil Bok-soon. Yim told OSEN, via The Chosun Ilbo, that the Jeon scene was the first time they had matched lines. "That moment was monumental for me." He also said her gaze still carries power in a short appearance.
https://www.youtube.com/watch?v=PItlVyrf15U
Week two, Breaknews cited Netflix's Top 10 board. Mantis sat at number two among non-English films, 13.8 million views, 57 country lists. The official trailer from Netflix K-Content had already sold the pitch. Vacation is over. The old company is dead. Everyone wants the chair. ,
Entertainment rumors and trivia aggregated from public reporting. Treat speculation as unverified unless a cited source confirms it.
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