Character Relationship Map: Monster

Characters

• Bok-soon (played by Kim Go-eun) — protagonist

  A young woman with a developmental disability who runs a street stall with her younger sister. Despite being labeled a 'psycho bitch,' she is brave, optimistic, and fiercely protective. After her sist...

• Tae-soo (played by Lee Min-ki) — protagonist

  A merciless and methodical serial killer who operates alone in a deserted forest. Adopted by a family that fears and exploits him, his isolation fuels his monstrosity. He kills multiple victims, survi...

• Na-ri (played by An Seo-hyun) — supporting

  A young girl whose older sister was murdered by Tae-soo. She becomes a target of the killer and allies with Bok-soon to escape. She survives the climactic restaurant massacre and leaves with Bok-soon.

• Ik-sang (played by Kim Roi-ha) — supporting

  Tae-soo's adoptive older brother who, along with his stepmother, took Tae-soo in but harbored deep disgust and fear toward him. He opportunistically uses Tae-soo and eventually conspires with gangster...

Canonical Relationships

Family, romantic, and professional connections based on plot evidence.

• Tae-soo → Ik-sang (Family Adoptive Brothers) — Their family bond is damaged by fear, exploitation, and betrayal.

  Ik-sang is described as Tae-soo's adoptive older brother, and the family took Tae-soo in as a young boy.

Story Dynamics

Alliances, conflicts, and narrative interactions that evolve throughout the story.

• Na-ri → Tae-soo (Conflict Target) — Na-ri is a surviving witness and direct target of Tae-soo's violence.

  Tae-soo chases Na-ri after killing her older sister and later takes Na-ri to the restaurant.

• Bok-soon → Na-ri (Alliance Ally) — They cooperate for survival and face Tae-soo together.

  Bok-soon joins up with Na-ri after Tae-soo kills Na-ri's older sister and begins pursuing the girl.

• Bok-soon → Tae-soo (Conflict Enemy) — Their conflict drives the revenge narrative and culminates in a lethal confrontation.

  Tae-soo kills Bok-soon's younger sister, after which Bok-soon plans revenge and ultimately fights him.

Story Analysis

A grieving woman transforms into an avenger while protecting another survivor from the killer who destroyed both their lives.

Plot Progression

1. A Fragile Market Peace — Bok-soon runs a street stall and focuses on saving money for her younger sister. Her ordinary routine is shattered when Tae-soo kills the girl.
2. Grief Finds an Ally — Consumed by grief and rage, Bok-soon begins planning revenge. She joins Na-ri, another survivor threatened by Tae-soo.
3. Family Betrayal — Tae-soo's adoptive family history reveals fear and exploitation. Ik-sang's failed phone arrangement and hidden plan place Tae-soo inside a restaurant trap.
4. Blood in the Restaurant — Tae-soo survives the gangster ambush despite severe injuries and kills those who arranged it. Na-ri appears to die, bringing Bok-soon into the final confrontation.
5. Revenge and Escape — Bok-soon kills Tae-soo after their brutal battle. Na-ri is revealed to be alive, and the two leave after Bok-soon hands over the phone.