The death of Himeno has been one of Chainsaw Man's most tragic storylines. She first came out as a little crude, attempting to attract a minor in Denji. But she quickly realized her mistake, and she struck a bargain with him to help her get close to Hayakawa in exchange for helping Denji find Makima.
She had no idea that Himeno would lose his life-fighting Samurai Sword and Sawatari shortly after their bond was made. She was a victim of the ambush on the Public Safety Division in Japan, which mercifully only saw the survival of people like Kobeni and Makima. Fans grew to like Himeno because she was the buddy Denji had always wanted, therefore the timing could not be worse. Unfortunately, the death has become much more tragic and sympathetic as viewers attempt to process her unexpected outcome.
Himeno of Chainsaw Man was Killed Out of Love
Because of her agreement with the Ghost Devil, Himeno gave herself in sacrifice during the assault. Knowing that Hayakawa had to murder the Gun Devil and eventually exact revenge on his family, she didn't want him to perish. She sadly vanished into oblivion as her devil contract ended because she had no idea that the villains would use the Snake Devil against them.
Himeno made it obvious that she was acting in Hayakawa's best interests as she passed. She even thought of him as her soul mate because he had been instrumental in her recovery from a previous loss. Hayakawa was tragically hospitalized after this battle, battling depression and clinging to his late partner's memories.
Hayakawa Gets the Reality from the Chainsaw Man
Surprisingly, a young woman arrives with letters as Hayakawa laments, sobs, and considers his future as a cigarette smoker. Since she turns out to be Himeno's sister, it's pretty endearing. All of their correspondences, which serve as a confirmation of Himeno's conviction that he was her genuine love and of her desperation to save him and release him from his own desire for vengeance, are left with him.
This could help him heal, but it could also break him, knowing he ignored their feelings for each other and a chance at happiness. Hayakawa was obsessed with the job, which is why he's collaborating with a new, monstrous devil to avenge Himeno. As his psyche is shattered, he may become more distracted than motivated. On the other hand, he may become overly emotional, making him a liability when engaging the enemy.
Finally, he feels that his selfishness did not pay off, and that he may have been robbed of another chance at happiness. Hopefully, he will be able to ride out this tragic wave, but as Hayawaka begins to cut a human, vulnerable, and frail figure, the elements are in place that could make him weaker in the field, allowing the villains to capitalize. After all, he's not used to listening to his heart and feelings, so it'll be interesting to see how he deals with these letters and the ghost of Himeno as Chainsaw Man progresses.