Hmm, this is a pretty sensitive topic, and also spoilery, so I’ll put my thoughts under spoiler tags. I had female MC and male Jun, and yeah he is sexist for sure…and vulgar, uncivilized, aggressive, and a lot of other things…though I think he does appear to respect her as an equal (or even superior) when it comes to the sword, and I don’t think he actually desires a sex slave. Here’s why:
Perhaps the biggest tip off is that Jun shows a lot revulsion when he is confronted with actual sex slavery at the masquerade party. So either, he doesn’t care much for it in reality, it isn’t who he wants to be, or he is remembering his own past and part of him wants to change.
During the sex scene before Jun talks about his past, MC says something like “I know we like our role play, but I can’t help but feel like I’m hurting you.” So I’m not so sure Jun is as comfortable with it all as it seems.
At one point early on you can pick a dialogue option, “what does it matter what I think, I’m just a dog…” and he responds “you won’t be a dog forever”. Implying he sees the situation as beneath the MC…he’s just waiting for her to find her self respect (which she clearly lost after the events of book 3). In the meantime, he’s willing to do or be whatever he needs to be to make that happen…even become a demon.
When the MC finally does remember the Jigoku and gets her self respect back, Jun gives her jacket back immediately, and also starts showing his own fears and vulnerabilities more openly…
If you go through with the romance, there is a role reversal happening…where the MC is starting to view the idea of attachments and fate as something less terrible for a change…and Jun is learning that sometimes you have to embrace change, and let go of the things you love to save them. His final act is to literally cut off his own arm and set her free so that she can live, and not be dragged back down into hell.
I thought it was clever, the analogy of the red string of fate as a leash… and it was cleverly written, because every time the string would tighten, I’d get an uneasy feeling and think to myself “that dick!” until eventually I realized the string was just getting tighter and shorter because they were thinking about one another. It was interesting how the string transforms and literally goes from iron chains, to a life line, to something they used to fight with the Jigoku together in battle…in a completely new way Sensei never taught them to do. In fact, Sensei warned them against working together, back in chapter 1, if you told him you and Jun got the apple together.