The Mantis: Original Sin (2025) begins with a series of brutal murders in a residential area that bear a striking resemblance to the killings committed decades earlier by Jung Yi-shin, a notorious female serial killer known as the "Mantis" who murdered five men before being captured and imprisoned. The police are baffled by the new murders, which mimic the distinctive modus operandi of Yi-shin, suggesting a copycat killer is at work.

Detective Cha Soo-yeol, a skilled and accomplished investigator, is assigned to the case. He is the estranged son of Jung Yi-shin and has harbored deep resentment toward his mother for her crimes and the stigma attached to their family. Despite his personal feelings, Cha Soo-yeol is forced by the authorities to collaborate with his mother, who remains incarcerated, to gain insight into the killer's methods and motives. This uneasy partnership is fraught with tension, as Cha struggles to reconcile his professional duty with his complicated emotions toward Yi-shin.

The investigation unfolds with Cha Soo-yeol and Jung Yi-shin exchanging information and theories. Yi-shin's intimate knowledge of the original murders provides crucial clues that help narrow down suspects and understand the psychological profile of the copycat. Throughout their interactions, flashbacks reveal Yi-shin's past crimes, her capture, and the impact on her family, especially on Cha Soo-yeol's childhood and development.

As the murders continue, the copycat killer escalates the violence, leaving behind cryptic messages and staging the crime scenes to taunt both the police and Yi-shin. Cha Soo-yeol faces internal conflict as he begins to see parallels between his mother's cold, calculated nature and the emerging patterns in the current killings. He also confronts his own biases and the societal judgment he has endured due to his mother's infamy.

The investigation leads to several confrontations and close calls. Cha Soo-yeol pursues leads that take him through dark alleys, abandoned buildings, and tense interrogations. At one point, he narrowly escapes an ambush set by the copycat, who seems to anticipate the police's moves. Meanwhile, Yi-shin uses her cunning and manipulative skills to influence the investigation from behind bars, providing cryptic hints that only Cha can decipher.

A major turning point occurs when Cha Soo-yeol discovers that the copycat killer is someone from his own circle, someone who has been deeply affected by the legacy of the original Mantis murders. This revelation forces Cha to confront painful truths about trust, betrayal, and the long shadows cast by past sins.

In the climax, Cha Soo-yeol and Jung Yi-shin orchestrate a risky plan to lure the copycat into a trap. The plan involves Cha pretending to be vulnerable and accessible, baiting the killer to reveal themselves. The confrontation is intense and violent, with a detailed sequence of chase and fight scenes. Cha uses his detective skills and physical agility to outmaneuver the copycat, while Yi-shin provides strategic advice remotely.

The final confrontation ends with the copycat's capture, but not before a harrowing struggle that tests Cha Soo-yeol's resolve and forces him to make critical decisions about justice and redemption. The series closes with Cha Soo-yeol reflecting on his relationship with his mother, the nature of evil, and the possibility of breaking free from the past.

Throughout the series, the narrative is interspersed with flashbacks to Jung Yi-shin's original murders, her psychological state, and the impact on her family, providing a layered understanding of the characters' motivations and the origins of the "Mantis" legend. The emotional core centers on the fraught mother-son relationship, the burden of legacy, and the quest for truth amid darkness.

The ending of The Mantis: Original Sin (2025) culminates with the detective Cha Soo-yeol and his mother, the serial killer Jung I-sin (the Mantis), confronting the copycat killer and the dark legacy of their past. The series closes on a tragic and emotional note, revealing the cyclical nature of violence and the complex bond between mother and son, with each main character facing a fate tied to the consequences of their actions and the sins of the past.

In the final episode of The Mantis: Original Sin, the story unfolds scene by scene as follows:

The episode opens with Cha Soo-yeol, the detective who has spent his life hating his mother Jung I-sin for her brutal murders of five men decades ago, grappling with the emergence of a copycat killer who mimics the Mantis's signature crimes. This new threat forces Soo-yeol into an uneasy alliance with his mother, whom he has despised and feared.

The first key scene shows Soo-yeol and Jung I-sin sitting face to face in an interrogation room. Soo-yeol's cold demeanor contrasts with I-sin's calm, almost chilling composure. He accuses her of the pain she caused, while she reveals her own brutal motivations, saying things like, "I should have torn off every part attached to that guy's body," exposing the depth of her darkness.

As the investigation progresses, Soo-yeol and I-sin track the copycat killer through a series of tense and violent encounters. The copycat's identity and motives are gradually revealed, showing a twisted desire to continue the Mantis's legacy. Soo-yeol struggles internally with his hatred for his mother and the necessity of working with her to stop further murders.

In a climactic confrontation, Soo-yeol and I-sin face the copycat killer together. The scene is charged with tension, as Soo-yeol must rely on the very person he has condemned his whole life. The fight is brutal and emotionally fraught, highlighting the complex dynamics of trust and betrayal between mother and son.

After the copycat is subdued, the final moments focus on the aftermath. Soo-yeol reflects on the cycle of violence that has haunted his family and the city. Jung I-sin's fate is left ambiguous but suggests a return to incarceration or a form of self-imposed exile, acknowledging the consequences of her past actions.

The series closes with a poignant scene emphasizing the theme of tragedy repeating across generations. Soo-yeol, though victorious in stopping the copycat, remains burdened by the legacy of his mother's crimes and the emotional scars they have left. The ending underscores how attempts to protect loved ones can sometimes cause the greatest harm, and how buried truths inevitably resurface.

In summary, the main characters' fates at the end are:

• Cha Soo-yeol: Continues as a detective, burdened but resolute, having confronted both the copycat killer and his own conflicted feelings toward his mother.
• Jung I-sin (The Mantis): Faces the consequences of her past, likely returning to prison or isolation, her dark legacy cemented but her role in stopping the copycat acknowledged.
• The Copycat Killer: Defeated and captured, ending the immediate threat but symbolizing the ongoing cycle of violence.

This detailed ending scene by scene captures the emotional and narrative resolution of The Mantis: Original Sin, highlighting the tragic interplay of family, crime, and the inescapable shadows of the past.

Yes, several characters die in the TV show The Mantis: Original Sin (2025), primarily related to the serial killings central to the plot.

• Jung Yi-shin, played by Go Hyun-jung, is the original "Mantis" serial killer who murdered five men decades ago. These murders are the foundational deaths around which the story revolves. She was caught and sentenced to death, becoming a death row inmate.

• The five men murdered by Jung Yi-shin were killed in the past, before the series' present timeline. The exact circumstances of each murder are not detailed in the available summaries, but these killings established her notoriety as the "Mantis" serial killer.

• In the present timeline, copycat killings emerge that imitate Jung Yi-shin's style, leading to new deaths. These copycat murders drive the plot and force her son, Detective Cha Soo-yeol, to work with his mother to solve the case.

• The show's narrative tension is deeply tied to these deaths: the original five victims killed by Jung Yi-shin, the copycat victims, and the emotional and psychological consequences for the main characters, especially the son who has hated his mother for her crimes.

No detailed public information is available about additional character deaths, their exact timing, or the specific circumstances of each death beyond the original five murders by Jung Yi-shin and the subsequent copycat killings. The series focuses on the investigation and the complex relationship between the detective and his mother, the original killer.

In summary, the key deaths are:

• Five men murdered by Jung Yi-shin (the original "Mantis") decades ago, leading to her death row sentence.

• Multiple victims of copycat killings in the present timeline, which prompt the investigation.

The show's plot centers on these deaths and their impact rather than on a broad list of character deaths with detailed circumstances.

The TV show The Mantis: Original Sin (2025) does not have any publicly documented post-credit scene. None of the available detailed reviews, plot summaries, or official descriptions mention a post-credit scene or extra footage after the final episode. The sources focus on the main story, characters, and mood without reference to additional scenes beyond the ending.

If a post-credit scene exists, it has not been noted in reviews or viewer discussions as of now.

Jung Yi-shin is the central character known as the 'Mantis,' a female serial killer who brutally murdered five men two decades ago. Her chilling nickname comes from the female mantis's behavior of devouring the male after mating. She was imprisoned for these crimes but is brought back to assist the police when a new killer emerges mimicking her style. Her complex relationship with her estranged son, Cha Soo-yeol, who is a detective assigned to the case, forms a key emotional and narrative element of the story.

Cha Soo-yeol is Jung Yi-shin's son who has harbored deep resentment and hatred toward her his entire life due to her past as a serial killer. Despite this, he is forced to work with her when copycat killings begin, creating a tense and emotionally charged dynamic as they confront their painful past and the present threat together.

Yoon Hee-jin is a brilliant but troubled forensic pathologist and the mother of Park Ji-won. Set in 2005, she investigates a series of seemingly unrelated deaths that she believes are connected. Her obsession with uncovering the truth strains her relationships, especially with her young daughter. Her investigation leads her to confront dark forces that ultimately lead to her demise, making her a pivotal character in the prequel narrative.

The investigation into the copycat killings is central to the plot, involving the police bringing back Jung Yi-shin, the original 'Mantis,' to help solve the case. Detective Cha Soo-yeol, her son, leads the investigation despite his personal animosity toward her. The series explores their uneasy collaboration as they try to stop the new killer who mimics Jung Yi-shin's precise and brutal methods.

Key supporting characters include Detective Choi Min-ho, who is Yoon Hee-jin's reluctant ally and has his own secrets, adding emotional depth to the investigation. Another important figure is the enigmatic hospital director, whose benevolent façade hides sinister motives, creating tension throughout the series. Additionally, the retired legendary killer Dok-go and the trainee Jae-yi appear in the related storyline of the original 'Mantis' assassin narrative, enriching the broader universe of the series.

The TV show The Mantis: Original Sin (2025) is not family friendly and is best suited for mature audiences due to its intense crime thriller content involving serial killings and psychological drama.

Potentially objectionable or upsetting aspects for children or sensitive viewers include:

• Graphic and disturbing themes related to serial murder and violence.
• Psychological tension and nerve-shredding suspense that can be emotionally intense.
• Dark family dynamics involving hatred and trauma between a mother and son, with complex emotional and moral conflicts.
• Scenes depicting forensic investigations and crime scenes that may be unsettling.
• The overall tone is serious, with themes of obsession, trauma, and death.

No explicit spoilers are revealed here, but the show's mature subject matter and thriller elements make it unsuitable for children or viewers sensitive to violence and psychological distress.