Yoru's biggest failure in Chainsaw Man may not be her own fault (& it isn't Asa's either)

In Chainsaw Man, Yoru’s failure to transform Denji into a weapon has intrigued fans, initially blamed on Asa Mitaka’s resistance or Yoru’s weakened state. However, a deeper look points to Denji’s prior contract with Pochita, the Chainsaw Devil, as the true cause. In Tatsuki Fujimoto’s universe, devil contracts and the concept of ownership are binding and absolute.

Since Denji and Pochita’s bond predates Yoru’s interference, she cannot claim ownership over him. Thus, her inability isn’t a matter of power or intent, but a fundamental limitation imposed by the rules governing devil contracts and pre-existing allegiances.

Disclaimer: This article is a speculative theory and reflects the writer's opinion.

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Denji's contract with Pochita: The ultimate obstacle to Yoru's power in Chainsaw Man

Denji and Pochita as seen in the anime (Image via MAPPA)

Yoru's power operates on a fundamental principle: she can transform anything she considers her property into a weapon. Throughout the series, we see this demonstrated with various objects—most notably in the aquarium scene and with Room 606. Each successful weaponization follows a consistent pattern where ownership is established through some form of transaction or claim.

When Yoru attempted to weaponize the aquarium, she failed because her payment wasn't sufficient to claim true ownership. Conversely, Room 606 was successfully weaponized because she had legitimately rented it, establishing clear ownership rights. Denji's very existence depends on his contract with Pochita: to live a normal life.

This agreement wasn't just symbolic; it fundamentally altered Denji's physical being by merging Pochita's heart with his own. This contract established Pochita as having primary "ownership" of Denji's life, not in a possessive sense, but in terms of contractual rights and obligations.

The formation of a contract between a devil and a human results in the devil claiming part of the human's essence, which establishes a superior bond over any future ownership claims.

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The fusion of Denji and Pochita in Chainsaw Man: A contract beyond Yoru's reach

Denji and Pochita as seen in the anime (Image via MAPPA)

What sets Denji apart from other contract holders is that his bond with Pochita involves a complete physical fusion. When Yoru attempted to transform Denji into a weapon (specifically a spinal cord sword), she addressed only Denji, failing to acknowledge the dual nature of his existence.

Her power couldn't process the complex reality that Denji is simultaneously human and devil, with his life force inextricably tied to Pochita's heart beating within him. The Chainsaw Man universe establishes a clear precedent that prior contracts take precedence over new ones.

Pochita's claim on Denji, which keeps him alive through their merger, creates a foundational contract that cannot be overridden by Yoru's weaponization attempt. This situation isn't about power levels, but concerns the fundamental rules governing devil-human interactions in this world.

Just as a devil cannot form contradictory contracts with the same human, Yoru cannot claim ownership over something that has already been claimed through a previous contract. This limitation reveals something crucial about the nature of devils and their powers in Chainsaw Man. The established rules of contracts and ownership remain unbreakable for Yoru, regardless of her power level.

In Fujimoto's world, powerful devils operate under specific metaphysical laws that dictate their powers and how they interact with each other. By learning these rules, players gain a better understanding of why some powers succeed against certain enemies but not others, which increases strategic depth in the series' battles.

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Conclusion

Denji and Pochita as seen in the anime (Image via MAPPA)

The War Devil's failure to weaponize Denji exposes the complex rule system that supports the supernatural aspects of Chainsaw Man. This limitation strengthens the internal consistency of Fujimoto's world-building rather than acting as a plot hole or character weakness.

The connection between Denji and Pochita transcends conventional understanding of devil contracts, creating a unique entity outside the normal parameters of ownership that Yoru's powers depend upon.

In this light, her failure was inevitable—not because of any deficiency on her part, but because some bonds in the Chainsaw Man universe are unbreakable by conventional means.

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