Yoru

The War Devil who wields humanity's fear of conflict, forcing a student into a deadly hunt for Chainsaw Man.

Yoru is the War Devil from the Chainsaw Man series, a powerful entity born from humanity's fear of war. She enters into a contract with Asa Mitaka, a high school student who had already died and become a corpse during an incident involving the Justice Devil's manifestation. Unlike unique assumptions about Fiends, Yoru inhabits Asa's lifeless body as one of many Devils capable of this form (such as the Bat Devil), forcing her to hunt down Chainsaw Man to exact revenge for the complete erasure of the previous War Devil. While Asa seeks to break their pact, Yoru secretly plots to revive the Nuclear Weapon Devil and exploit global fear of war to regain strength.

Lore & Background

Devils in this world are born from collective human fears and grow stronger as those fears spread. Currently, Yoru explicitly states that the War Devil is weak because humanity does not fear war enough, which drives her plan to revive the Nuclear Weapon Devil to amplify that terror. Devils cycle between Hell and Earth upon death, but the Chainsaw Devil is a unique exception: consuming another Devil erases that concept permanently from existence and memory. This ability threatens Yoru, as she was completely erased by the chainsaw's power. To survive and regain strength, Yoru manipulates Asa Mitaka into forming a contract after her death, using her corpse as a Fiend vessel.

Reader's Guide

Yoru operates through her host, Asa Mitaka, forming a Fiend where the Devil shares the body with the human's consciousness. Their relationship is defined by conflict: Asa wants freedom from the pact while Yoru pursues revenge against Chainsaw Man. Yoru's power scales directly with humanity's fear of war, making global conflict essential to her survival strategy. She manipulates events through Barem Bridge and the Chainsaw Man Church, secretly controlled by Fami (the Death Devil in disguise), to destabilize Denji. Key moments include her defeat of the Falling Devil following America's nuclear reinvention and her final confrontation where she seemingly kills Pochita before being defeated by Denji's new hybrid form. Asa ultimately sacrifices herself to enable Denji's victory, ending Yoru's immediate threat.

Did You Know?

Yoru specifically represents the fear of war, but currently remains weak because humanity lacks sufficient fear of conflict in the present timeline.
The War Devil was completely erased from existence by the Chainsaw Man's power, prompting her revenge plot through Asa.