Mantis Netflix Thriller: Everything You Need to Know (Guide)

When Netflix announced Mantis, fans of Korean action thrillers immediately sat up and paid attention. Arriving September 26, 2025, Mantis isn’t just another streaming release—it’s a bold spin-off of the acclaimed 2023 hit Kill Boksoon. If you loved that film’s razor-sharp action and complex assassin underworld, you’ll want to know why Mantis Netflix is shaping up to be one of the must-watch movies of the year.

A Spin-Off That Expands the Assassin Universe

One of the reasons Mantis has created so much buzz is its direct connection to Kill Boksoon. Writer-director Byun Sung-hyun, who built the assassin universe in the original, co-wrote this new story with Lee Tae-sung—who now makes his feature directorial debut. Fans may remember a throwaway line in Kill Boksoon where the assassin “Mantis” was mentioned as being “on vacation.” That tiny reference has now exploded into a full-length movie, proving Netflix’s commitment to building a cinematic universe in the same way Hollywood franchises do.

The Story of Han-ul, Codename “Mantis”

At the heart of Mantis is Han-ul, played by Yim Si-wan (Squid Game seasons 2 and 3, Unlocked, Emergency Declaration). Han-ul is an elite assassin who has been away from the bloody world of contract killing, only to return and find everything in chaos.

Read Also – Alice in Borderland S3 Ending

The chaos stems from the death of Cha Min-kyu (played by Sul Kyung-gu), the head of MK Enterprise—the assassin organization introduced in Kill Boksoon. With the leadership vacuum, the underworld has fallen apart. For Han-ul, coming back means walking into a storm of shifting loyalties, broken rules, and violent rivalries.

Rivals, Mentors, and Old Wounds

No assassin tale is complete without complicated relationships, and Mantis Netflix doesn’t disappoint.

• Park Gyu-young (Sweet Home, Celebrity) plays Jae-yi, Mantis’s former training partner and rival. She’s highly skilled, but her resentment and unresolved feelings toward Han-ul make her a dangerous wildcard.
• Jo Woo-jin (Narco-Saints, Mr. Sunshine) portrays Dok-go, a retired legend and founding member of MK Enterprise. Once Han-ul’s mentor, Dok-go has returned as CEO to restore order—but his motives might not be as simple as they seem.
• Adding more intrigue is Choi Hyun-wook as Benjamin, a young tech entrepreneur who manipulates Jae-yi’s insecurities against Mantis.

These three key figures create a triangle of power, trust, and betrayal that pushes the story forward.

Expanding the Assassin Universe

For fans of Kill Boksoon, one of the big questions was how Mantis would connect to the original. Here’s what we know:

• Gil Boksoon (Jeon Do-yeon), the original film’s protagonist, appears briefly, tying the stories together.
• The same MK Enterprise setting and rules are back, but with new leaders and rivalries.
• The events of Mantis unfold after the death of Cha Min-kyu, directly impacting the hierarchy of killers introduced in the first film.

This layered continuity is part of why Netflix is banking on Mantis Netflix to appeal globally—it’s not just a one-off, it’s part of a growing franchise.

Behind the Scenes: Production and Training

Filming took place between August and December 2024, under the banner of SEE AT Film Co., LTD—the same studio behind Kill Boksoon and other Korean hits like Love and Leashes and Kingmaker.

The actors didn’t just show up and throw punches. Yim Si-wan trained specifically in blade combat, while Park Gyu-young went through rigorous close-quarters combat training. This dedication means the fights won’t just look stylish—they’ll feel raw, personal, and painful, which is exactly what fans of Korean thrillers crave.

Marketing That Knows Its Audience

Netflix has made sure the world is paying attention.

• A teaser trailer dropped August 26, 2025, followed by an official trailer on September 10, 2025.
• The tagline? “The rules are broken. Who dares take the shadows?”—a chilling nod to the chaos in the assassin world.
• The campaign leans into comparisons with John Wick, but with a distinctly Korean edge that sets it apart.

Considering Kill Boksoon racked up over 63.3 million viewing hours, Netflix clearly hopes Mantis will ride that same wave of global hype.

The Cast You’ll Recognize

Korean thrillers have been winning over audiences worldwide, and Mantis Netflix has a cast stacked with familiar faces:

• Yim Si-wan (Squid Game, Unlocked) as Han-ul / Mantis
• Park Gyu-young (Sweet Home, Celebrity) as Jae-yi
• Jo Woo-jin (Narco-Saints, Goblin) as Dok-go
• Sul Kyung-gu as Cha Min-kyu
• Jeon Do-yeon as Gil Boksoon
• Supporting roles include Jeon Bae-soo, Bae Gang-hee, Yoo Su-bin, and more.

What Sets Mantis Apart

Plenty of assassin thrillers flood Netflix, but Mantis stands out for a few reasons:

1. It’s part of a growing franchise. Just like Hollywood’s Marvel or John Wick universes, Mantis Netflix is helping build an interconnected assassin world.
2. It balances action with drama. While the fights will thrill you, the relationships—mentor vs. student, rivals turned enemies—give the story emotional weight.
3. It reflects global tastes. With audiences in the US, UK, Canada, Australia, Germany, and Switzerland craving Korean thrillers, Netflix knows it has a hit formula here.

Don’t Confuse It with Queen Mantis

Here’s a quick note: Mantis Netflix is completely separate from SBS’s Queen Mantis TV series. While both share the Korean word “Samagwi” (mantis), the Netflix movie is an action spin-off, while Queen Mantis is a crime drama. So, if you’re scrolling and see both, don’t get mixed up.

Technical Details

• Runtime: 113 minutes (1h 53m)
• Rating: TV-MA (expect plenty of violence)
• Language: Korean with subtitles
• Distribution: Netflix, worldwide, across all subscription tiers

Final Thoughts: Why You Should Watch Mantis on Netflix

If you’re tired of generic action flicks, Mantis Netflix might be the refreshing edge you’re waiting for. It’s gritty, it’s stylish, and it carries the emotional punch that made Kill Boksoon a global success.

The combination of Yim Si-wan’s intense performance, Park Gyu-young’s complex rival role, and Jo Woo-jin’s return as a mentor-turned-CEO creates a triangle of drama that’s impossible to ignore. Add in high-octane fight choreography, sleek direction from Lee Tae-sung, and the global reach of Netflix, and you’ve got a movie worth your Friday night.

So mark your calendars for September 26, 2025. The rules are broken, the shadows are calling—and the assassin known as Mantis is ready to take them back.