
basically onaga is a conventional cute girl with everything going for her and she should be happy as she says in the beginning, but we clearly learn she isn't and instead she feels hollow because everything in her life is "good' but monotonous. She doesn't have any real passions or close relationships, and is shown staring silently at the functional families and friend groups that sit at her job.
Kawashibara is the exact opposite, he is not conventional at all and a social pariah but he has the one thing she doesn't; genuine passion and a clear soul whenever he dresses up in girls clothes and does girly things. Onaga lives vicariously through Kawashibara's happiness by providing him with girly things like makeup and clothes. She enjoys being responsible for his happiness and can find purpose by delivering these small joys to him.
When she learns that he wants to confess to somebody and actually move forward with his life instead of staying her plaything, she lashes out and says that she was the only reason he got thus far; and that she is the harbinger of his happiness and without her it's impossible.
obviously he gets rejected and now onaga can be his deity once again and she wins in the end ig

No, I think it’s more like she likes him and lashed out because she realized it was dumb of her to assume he’d be looking for that in her. I think she is possessive and bored with the monotony but especially after reading all of this author’s works I get the feeling that the girl is a specific persona that reflects the author. I think that this one him is viewing the life of a queer/trans woman through the lenses of the woman he has/desires inside of him.
If you have the time to read his other work he has an ongoing theme of similar looking women who disassociate from life and take on this perversion of human psychology. It’s always a disconnect between body and spirit and the more I get to reading his works the more I come to understand that it’s not just some shallow fantasy about sex and control, it’s usually a complex mix between the psychological effects of life, living and death within a person who doesn’t belong in their own skin(or in regular society).
As I read his works they all feel very personal and connected to one another, like a continuation of his own psyche. I think it would be hard to see what any of his short works elude to unless you took the time to read some of his longer works and read into some of his personal background.
I think the easiest one to see this from is his work “inside Mari”. I’ve just finished reading “trails of blood” as well and it is… disturbing but real.
Ps.. ik you posted this like a year ago, I just needed to say this bc i think all the comments that I see are slightly misguided. Yours sounded the closest to what I am thinking atm.
yoochan said he falls in love based on person not on gender so I hope they throuple and live happily ever after