Character Relationship Map: Cold Fish

Characters

• Nobuyuki Shamoto (played by Mitsuru Fukikoshi) — protagonist

  The timid protagonist who runs a small fish shop. After being coerced into a partnership with serial killers Yukio and Aiko Murata, he is forced to assist in disposing of corpses. Over time, he succum...

• Yukio Murata (played by Denden) — protagonist

  An eccentric fish shop owner who secretly operates as a sociopathic serial killer. He scams, kills, and disposes of threats while forcing Nobuyuki into complicity through manipulation and violence. He...

• Akio's Brother (played by Masaki Miura) — supporting
• Mitsuko's Boyfriend (played by Kazuma Yamane) — minor
• Akio's Brother (played by Ichiro Hashimoto) — minor
• Akio's Brother (played by Ryohei Abe) — minor
• Akio's Brother (played by Suwaru Ryû) — minor
• Akio's Brother (played by Hideo Nakaizumi) — minor
• Takayasu TsuTsui (played by Tetsu Watanabe) — supporting

  A detective who previously attempted to recruit Nobuyuki to investigate suspicions about Yukio and Aiko. He arrives at the cabin at the end, finding Nobuyuki outside before rushing inside to discover...

Canonical Relationships

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

• Akio's Brother → Akio's Brother (brother)
• Akio's Brother → Akio's Brother (brother)
• Akio's Brother → Akio's Brother (brother)
• Akio's Brother → Akio's Brother (brother)
• Takayasu TsuTsui → Nobuyuki Shamoto (Professional Investigative Contact) — Takayasu treats Nobuyuki as a potential investigative source and encounters him at the end.

  Takayasu previously tried to recruit Nobuyuki to confirm suspicions about Yukio and later finds him sitting outside the cabin.

• Nobuyuki Shamoto → Yukio Murata (Professional Coerced Business Partner) — A business partnership becomes a mechanism of coercion and criminal complicity.

  Yukio invites Nobuyuki to become business partners and later forces him to assist with disposing of corpses.

Story Dynamics

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

• Nobuyuki Shamoto → Mitsuko's Boyfriend (Conflict Violent Adversary) — Nobuyuki reacts violently to the boyfriend's presence during his attempt to impose family control.

  When Mitsuko's boyfriend arrives outside the family dinner, Nobuyuki knocks him unconscious after Mitsuko leaves the table to meet him.

• Takayasu TsuTsui → Yukio Murata (Conflict Investigator) — Takayasu investigates the criminal activity surrounding Yukio.

  Takayasu and another detective previously tried to recruit Nobuyuki because they suspected Yukio and his wife.

Story Analysis

A timid shopkeeper is manipulated into criminal complicity and ultimately reproduces the violence that destroyed his moral identity.

Plot Progression

1. A Door Into Temptation — Nobuyuki struggles with an unhappy home life and runs a modest tropical fish shop. Yukio intervenes during a theft incident, then offers Nobuyuki access to a larger business and greater wealth.
2. The Profitable Trap — Nobuyuki reluctantly accepts Yukio's proposal and enters a more lucrative fish business. The apparent opportunity gradually becomes a coercive relationship built on pressure and fear.
3. Complicity In The Forest — Yukio's criminal operation is revealed, and Nobuyuki is forced to help process and dispose of victims. Repeated humiliation and intimidation steadily destroy Nobuyuki's moral resistance.
4. Violence Comes Home — After killing Yukio, Nobuyuki carries the criminal logic back into his household. His attempt to stage a normal family dinner collapses into attacks against the people around him.
5. The Final Collapse — Nobuyuki returns to the cabin and completes another killing before detectives arrive. He attacks a family member and ends his life in front of his daughter.