Yuna's character arc is very interesting and I don't think I've ever seen anything quite like it before. It starts with her as an insecure flighty shut-in who then finds out that the person she's been idolizing (she basically saw Rena as the perfect woman at the start) is in love with her. So far that's pretty standard shoujo. But unlike in other stories where Rena's love would teach her self-worth etc, her romance has actually only deepened her issues. Yuna hates herself so much that she can't understand why Rena would love her, so she swings between excessive clinginess, irrational jealousy, and in this chapter nonstop seduction (because she subconsciously believes Rena could only lover her for her body). These behaviors make her feel guilty, which only feeds into her self-destructive cycle. And her lack of any external support system whatsoever means she has no external point of view to give her any perspective. She's probably the best-written character Morinaga's ever made, honestly.
All this does raise a concern, however. Morinaga's done such a good job depicting Yuna's ongoing self-destructive spiral that I kind of don't see how she can pull Yuna out of it without a massive asspull? As much as Rena loves her (and holy shit is Yuna lucky to have met Rena because she would be a prime target for abusers otherwise), she's self-confident and self-assured enough that I don't think she's capable of really understanding what Yuna is going through. Everything she does that to most people would reassure them just deepens Yuna's anxieties further. But Morinaga doesn't really do sad or even bittersweet endings so...I guess we'll see?
