Netflix’s Mantis: The Rules Are Broken. A New Killer Takes the Shadows

In the meticulously constructed cinematic universe of contract killers, where order is maintained by a rigid, almost corporate, set of rules, chaos is the ultimate contagion. Netflix’s new action thriller, Mantis, plunges directly into such an epidemic. The film, whose Korean title is Samagwi, operates not as a standalone narrative but as a calculated expansion of the world first delineated in the 2023 feature Kill Boksoon. It explores the power vacuum that follows the collapse of an established hierarchy, a premise encapsulated by its stark tagline: “The rules are broken. Who dares take the shadows?”. This is more than a simple genre exercise; it is a clinical examination of ambition and survival in a state of anarchic flux. The film functions as a significant artifact of a broader industrial strategy, one where individual stories are no longer disposable commodities but foundational elements in the cultivation of long-term, interconnected intellectual property. It signals a maturation in the global streaming paradigm, moving beyond the production of singular hits toward the deliberate architecture of entire narrative ecosystems.

Narrative Architecture: A Triangular Power Struggle

The film’s narrative economy is driven not by labyrinthine plotting but by the volatile triangulation of its central characters, whose psychological fractures and shifting allegiances provide the story’s primary engine. The catalyst is the death of Cha Min-kyu, the formidable leader of the assassin agency MK Ent., an event that sends the entire contract killer industry into a tailspin. Into this void steps Han-ul, an ace assassin codenamed “Mantis,” portrayed by Yim Si-wan. Returning from a prolonged hiatus, he perceives the systemic collapse not as a crisis but as an opportunity, promptly establishing his own startup, the “Mantis Company”. This entrepreneurial framing deliberately subverts genre expectations, mixing the killer’s story with the theme of a young person starting out in society, aiming to show a more human and less flawless side to its assassins. His re-entry forces a reunion with Jae-yi, played by Park Gyu-young, a former trainee and friend who has since become a formidable killer in her own right. Their shared history is a complex tapestry of camaraderie and nascent romance, made precarious by Jae-yi’s simmering jealousy over Han-ul’s innate talent. This dynamic is further complicated by Benjamin (Choi Hyun-wook), an external investor and CEO of an action gaming company who, recognizing Jae-yi’s skill, challenges her loyalty to Han-ul. Completing this unstable structure is Dok-go, a legendary retired founder of the original organization, played by veteran actor Jo Woo-jin. Disturbed by the crumbling of his legacy and hating to be “treated as an old man in the back room,” he emerges from the shadows to reclaim control. The narrative tension is amplified through terse, barbed exchanges that lay bare the characters’ mistrust, transforming the film into a tense exploration of personal betrayal where professional violence is merely a symptom of deeper emotional conflicts. This structure functions as a potent generational allegory. Dok-go represents the old guard, a figure of institutional memory attempting to restore a legacy system. Han-ul and Jae-yi are the disruptive new generation—the “MZ killers,” as the filmmakers have described them—who view the wreckage of the old world as fertile ground for ambition. The film thus stages a fundamental ideological schism, where the “broken rules” signify not just industry regulations but the erosion of societal traditions, elevating the narrative from a straightforward action piece to a nuanced social commentary.

Mantis

Directorial Vision: The Kinetics of Emotion

Mantis marks the feature directorial debut of Lee Tae-sung, whose apprenticeship as an assistant director on polished genre pieces like The King, The Policeman’s Lineage, and the film’s direct predecessor, Kill Boksoon, is evident in the final product’s visual confidence. Further ensuring a consistent creative DNA, the screenplay was co-written by Byun Sung-hyun, the director of the original film. Lee’s authorial signature, however, emerges in his treatment of action not as spectacle but as a physical manifestation of his characters’ internal states. He posits that the film’s narrative is propelled by subtle emotional shifts and personal judgments, and in a key directorial choice, instructed martial arts director Ryu Seong-cheol to design the fight choreography as a direct extension of those emotions. This philosophy is most clearly articulated through the characters’ signature weapons, each a carefully chosen signifier of their psychology. Han-ul wields a double-sided sickle, a weapon whose sleek, precise, and dualistic nature mirrors his own persona. Jae-yi’s weapon is an exaggeratedly long sword, its sweeping, attention-demanding movements a clear externalization of her ambition and underlying inferiority complex. Dok-go, the veteran, employs the tonfa, a practical tool of both offense and defense whose heavy, impactful strikes convey his resilience and grounded experience. This deliberate choice to arm modern assassins with almost archaic, personalized weapons is an act of stylization that removes the violence from the realm of gritty hyper-realism. Instead, the action sequences function as kinetic, non-verbal dialogues—operatic ballets of violence that articulate the power struggles, jealousies, and desperation that the characters are otherwise unable to express.

Character Study: The Ascendance of Yim Si-wan

The film’s gravitational center is unquestionably the performance of Yim Si-wan as Han-ul, a role that serves as the culmination of a multi-year career pivot. Originally a member of the K-pop group ZE:A, Yim built his formidable acting reputation on a foundation of earnest, empathetic portrayals in acclaimed projects such as the legal drama The Attorney and the seminal workplace series Misaeng: Incomplete Life. A decisive shift began with his turn as an undercover cop with wavering loyalties in the neo-noir The Merciless, a role that first showcased his capacity for moral ambiguity. This was the beginning of a calculated exploration of darker archetypes, including the unhinged bio-terrorist in Emergency Declaration, the chilling cyberstalker in Unlocked, and his internationally recognized villainous role in Squid Game. His portrayal of Han-ul in Mantis is a synthesis of this entire trajectory. He embodies the “representative MZ killer”—stylish, individualistic, and disdainful of convention. Yet, in a specific acting choice, Yim layers this persona with a concealed warmth, a vulnerability that is deliberately masked by a prickly, defensive exterior. This creates a compelling anti-hero whose internal conflicts are palpable. The performance weaponizes the audience’s expectation of sincerity, derived from his early career, to make his capacity for violence and moral ambiguity all the more unsettling. It is a meta-performance that draws power from the viewer’s familiarity with his filmography; the ghost of his Misaeng persona haunts the hardened shell forged in The Merciless, resulting in a character of profound and compelling complexity.

The Ensemble and the Ecosystem

While anchored by Yim Si-wan, the narrative integrity of Mantis is fortified by a meticulously curated ensemble whose dedication was such that, according to the lead actor, the set “smelled strongly of pain-relief patches”. Park Gyu-young, known for her roles in Netflix hits like Sweet Home, delivers a nuanced performance as Jae-yi, a character whose motivations are a volatile cocktail of ambition, affection, and profound jealousy toward Han-ul. Her portrayal provides the film with its crucial emotional counterpoint. As the fading legend Dok-go, Jo Woo-jin embodies the weight of history, a formidable figure who provides a grounded, intimidating presence that serves as a powerful obstacle to the aspirations of the younger generation. The film’s connection to its predecessor is solidified through the strategic use of cameos by Sul Kyung-gu and Jeon Do-yeon, who briefly reprise their roles as Cha Min-kyu and Gil Bok-soon. These appearances are more than fan service; they are a critical narrative device that firmly anchors Mantis within its established universe. The film also serves as a platform for emerging talent, featuring the feature film debuts of young actors Choi Hyun-wook, Bae Gang-hee, and Hwang Sung-bin. The casting of Yim Si-wan and Park Gyu-young, both alumni of the global phenomenon Squid Game, represents a particularly astute piece of marketing synergy. Though their characters did not interact in that series, their reunion here is a calculated move to attract a broad international audience, demonstrating a highly integrated approach to leveraging a global content library.

Industrial Context: The K-Content Gambit

To fully appreciate Mantis is to situate it within the macroeconomic landscape of the global streaming wars. The film is not merely a creative work but a strategic asset in Netflix’s high-stakes campaign to achieve market dominance through high-quality, localized content. South Korea has become the crown jewel of this strategy, backed by a staggering $2.5 billion investment pledge over four years. This influx of capital has dramatically elevated production values, with the average cost per K-drama episode surging from around $360,000 in 2015 to upwards of $2.4 million for Netflix originals like Sweet Home. Netflix’s success is predicated on a localization model that empowers local creators to tell Korean stories for a domestic audience first, which then find remarkable global resonance. This “ripple effect” has been shown to spark worldwide interest in Korean culture, language, and tourism, creating a potent soft-power feedback loop. Mantis, produced by SEE AT Film Co., LTD (the same house behind Kill Boksoon), is a quintessential product of this model: it is a high-production-value genre film; it elevates a first-time director, demonstrating a commitment to nurturing new talent; and it employs the franchise-building spin-off model to create a durable, long-term asset. This approach represents a solution to one of the streaming industry’s most pressing challenges: content saturation and the need for cost-effective IP generation. In a hyper-competitive market, the spin-off model is a more capital-efficient method for generating engaging content than the perpetual, high-risk search for the next mega-hit. By expanding the Kill Boksoon universe, Netflix is not just releasing another film; it is deepening the intrinsic value of its library and creating a network effect where one property drives engagement with another. This industrial logic—the strategic shift from producing shows to building universes—is the defining characteristic of the current phase of media consolidation, and Mantis is a perfect illustration of this strategy executed with precision.

Mantis is a sophisticated, character-driven action film that succeeds entirely on its own creative terms. It is a showcase for Lee Tae-sung’s confident directorial debut and a confirmation of Yim Si-wan’s status as one of the most compelling and versatile actors of his generation. Simultaneously, it serves as a fascinating indicator of the future direction of global streaming content, a testament to the symbiotic and world-conquering partnership between the creative vitality of contemporary South Korean cinema and the industrial might of its most significant global distributor.

The film premiered worldwide on Netflix on September 26, 2025.