The most glaring qualm I took with this is the use of the words "Freaked out," and "Messed up."
Secondly, as I've been reading these chapters, all this time she spent getting drunk just struck me as dumb. I wish I had a more professional word or phrase to use, but nothing seems to carry the right weight and tone to. Rosaline is just acting dumb. In fact her entire side of the plot seems to be carried or progress if you'd like, by her being dumb. She's too dumb to actually have a sit down (so to speak) with Rosen and figure things out. She's too dumb to ask him why, if he can control her "at any time," as she puts it, he does not take control of her all the time. She's too dumb to ask about her sister. She's too dumb to get more information about Black Rose. She too dumb to care about other people's problems and instead just wants to whine and whine and whine about everything. She's just too dumb to do anything.
And in part the reason I get on her case so much about it is probably because I like the character so much. I mean, seeing her do these really dumb things just makes me want to groan and strangle her. And that probably says quite a bit about the high quality of the writing and character development. So maybe that's a GOOD thing I feel that way.
But at the same time I, as the reader, can only look at this plot being carried in the same way most zombie movies are carried. And that is, "Someone does something stupid and suddenly everyone is in danger." It's called "idiot plotting." I'm half expecting her to suddenly throw open a door and let in all the monsters in an attempt to save an annoyingly yappy dog. In the case of this story, you're artificially creating tension by having a potential catastrophe coming, but only because people are being dumb, not because they're just making bad decisions.
Rosaline isn't gathering information and making a selfish decision with it. She's blatantly ignoring everything with only the self interest of revenge. And this brings us to the third point.
The third qualm I have with the piece is that Rosaline is such a vastly different character from where she came from. Not because of any real development, but because she just keeps being dumb (as I said above, but I hope by beating this dead horse enough It is making the point I want it too). But when we first meet her, she's not dumb. She brave and self-sacrificing. She attacks a much bigger/stronger/tougher/powerful man who's hurting people. The primary motivation is to save her sister, and that's makes her cool. It was one of the things that drew me to the character. But here we don't see that person. We get a glimpse when she fights the big monster thing, but she's spent so much time drinking and being dumb that the event seems a stark contrast to the character's state which seems in contrast with the character's original conception. I mean, if she was that brave before, out of the blue like that, why wouldn't she be now? Drinking might quiet Rosen, but why wouldn't she want to snatch as much from him as she can? She seems to only think he's manipulating her because that's what the author wants us to think, not because there actually seems a reason for it. Instead of brave (we're excluding smart because jumping someone that tough and getting your bodies merged does not rank on the smart scale) she's just whiny. And dumb.