When Tatsuki Fujimoto wrapped up the first arc of Chainsaw Man, fans were left reeling. Denji had literally consumed the Control Devil. The world felt quiet for a fleeting second. Then came the bird. Or, more accurately, the Yoru War Devil—a scarred, owl-like entity that immediately upended the power scaling and emotional stakes of the series.
Honestly? Yoru is a mess. A fascinating, terrifying, and deeply incompetent mess.
If you’ve been following the manga, you know she isn’t just another villain. She's one of the Four Horsemen, yet she starts her journey at the bottom of the food chain because humanity has started to forget the sheer visceral terror of war. That’s the core of her character. She’s a god-tier entity suffering from a massive ego bruise, forced to share a brain with a high school loner named Asa Mitaka.
The Weird Mechanics of Yoru the War Devil
How does her power actually work? It’s not just about "being strong." It’s about guilt.
Most Devils in the Chainsaw Man universe gain power through fear. The more people fear spiders, the stronger the Spider Devil gets. Yoru is different. While she feeds on the fear of conflict, her specific ability—Object Creation—is fueled by a twisted version of human emotion. To turn something into a weapon, she has to "own" it.
Ownership, in Yoru’s eyes, is subjective.
If she feels she owns you, she can turn your spinal cord into a sword. It’s gruesome. It’s bizarre. But here’s the kicker: the more guilt Asa or Yoru feels about the transformation, the more powerful the resulting weapon becomes. This creates a fascinating narrative loop. To be the strongest version of herself, the War Devil actually needs to feel bad about what she’s doing.
It’s a complete inversion of the traditional "heartless monster" trope.
The Relationship with Asa Mitaka
You can't talk about Yoru without talking about Asa. They are two sides of the same coin, literally sharing a prefrontal cortex.
When Yoru first appeared, she claimed she was taking over Asa’s body to hunt down Chainsaw Man. She wants her lost comrades back. She wants her dignity back. But as the chapters progress, the line between them blurs. Yoru starts feeling Asa’s crushes. She gets flustered. She experiences the crushing social anxiety of a teenage girl who doesn't know how to talk to boys.
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It’s hilarious. It’s also deeply tragic.
Fujimoto uses this duality to explore the idea of identity. Is Yoru becoming more human, or is Asa becoming more like a Devil? Sometimes it’s hard to tell who is in the driver’s seat. They argue like sisters. They sabotage each other’s dates. It’s a roommate comedy where one roommate can turn the other’s boyfriend into a hand grenade.
Why the War Devil is Actually "Weak" (For Now)
Let’s be real: Yoru has been taking a lot of L’s.
In the current world of Chainsaw Man, there hasn't been a world war in a long time. Chainsaw Man—Pochita—actually ate the Nuclear Weapons Devil. He ate the World War II Devil. He literally erased the concepts of those horrors from human history.
Because those concepts no longer exist, Yoru is a shell of her former self.
She’s basically a veteran general who’s been relegated to a desk job and then forgotten. Her primary motivation isn't just "evil." It’s relevance. She hates Chainsaw Man because he took her "babies" (nuclear weapons) away. This makes her one of the most motivated characters in the series, even if she’s currently struggling to turn a classroom locker into something more lethal than a dull knife.
The Contrast with Makima
Everyone compares Yoru to Makima. It’s natural. They are both Horsemen.
But where Makima was cold, calculated, and terrifyingly efficient, Yoru is impulsive and emotional. Makima looked down on everyone. Yoru is constantly looking up, screaming at the world to notice her. This makes her a much more "human" antagonist. You almost want to root for her, even when she’s trying to murder the protagonist.
She represents the messy, destructive side of humanity, while Makima represented the sterile, suffocating side of order.
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The Evolution of the "Super Strong Steel" and Beyond
As the story moves into the later chapters of Part 2, we see Yoru’s power scaling start to shift.
The "Super Strong Steel" sword was just the beginning. The moment she realized she could use Asa’s feelings for Denji to create weapons, the stakes skyrocketed. We’re seeing a shift from Yoru using physical objects to Yoru using relationships as fuel.
Think about the implications.
If she can turn a memory or a bond into a weapon, she becomes the most dangerous entity in the series. It’s no longer about how sharp the blade is. It’s about how much it hurts to lose the person the blade was made from.
What People Get Wrong About Her Goals
There’s a common misconception that Yoru just wants to kill Denji.
That’s a simplification.
She wants to make Chainsaw Man vomit up the concepts he swallowed. She wants Nuclear Weapons back in the world. She wants the fear of War to return to its peak. If she kills Denji without achieving that, she loses. This puts her in a weird spot where she has to keep him close, leading to the bizarre "dating" subplots that have defined the first half of Part 2.
She’s a Devil playing at being a girl playing at being a Devil.
The Art of the Reveal
Fujimoto’s art style also changes when Yoru takes over. The eyes change. The scars appear. But more subtly, the posture shifts. Asa is slumped, hesitant, and awkward. Yoru is rigid, predatory, and arrogant. This visual storytelling is crucial because it reminds the reader that even in the quiet moments, a primordial force of destruction is just an inch away from the surface.
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The scars are a mark of her previous battles with Chainsaw Man in hell. They aren't just a design choice; they are a constant reminder of her failure.
How to Understand the War Devil’s Future
If you want to stay ahead of the curve on where Chainsaw Man is going, you have to watch the "Guilt Meter."
Every time Asa does something she regrets, Yoru gets a power-up. This suggests that the endgame of Part 2 isn't a massive physical battle, but an emotional breaking point. If Asa finally snaps and loses her sense of morality, Yoru might finally regain her full strength.
But would she still be Yoru?
Or would the two souls have merged into something entirely new?
The series is leaning heavily into the idea of "becoming what you hate." Asa hates Devils; she is half-Devil. Yoru hates humanity; she is becoming increasingly human. It’s a collision course that can only end in one of them—or both—being completely transformed.
Key Takeaways for Fans
- Watch the Guilt: The strength of Yoru’s weapons is directly proportional to Asa’s internal suffering.
- The Horsemen Connection: Yoru is the younger sister of Fami (Famine) and Makima (Control). Their sibling rivalry is literally world-ending.
- The Pochita Factor: Yoru doesn't just want to kill Chainsaw Man; she wants to retrieve the concepts he erased from existence.
- Ownership is Key: If Yoru perceives she owns something, it’s a weapon. This includes people, places, and potentially even abstract concepts.
Moving Forward with Part 2
To really grasp the trajectory of the Yoru War Devil, you need to stop looking at her as a final boss and start looking at her as a co-protagonist. She is the catalyst for Asa’s growth, and Asa is the catalyst for Yoru’s potential redemption—or her ultimate descent into madness.
The best way to track this is to re-read the chapters where Asa and Yoru have their private "mind-space" conversations. Pay attention to the background details. Notice how Yoru reacts to things Asa likes.
The next step for any serious reader is to look back at the Horsemen lore established in Part 1. Compare the way Makima spoke about her "sisters" to how Yoru and Fami actually interact now. There is a massive gap between the legend of the War Devil and the reality of the girl currently living in a messy apartment.
Keep an eye on the weapons. The more personal the name of the weapon, the more dangerous the situation. When Yoru stops naming things after classroom supplies and starts naming them after people she actually knows, that's when the real war begins.