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.