Well, that's what I was writing about before, when I kept using the Monster word. Basically I was working off of what you said about blood manipulation and bone manipulation, I was just trying to take it in a somewhat different direction. Like maybe she finds when she does the manipulation it makes her strong and tough, but also changes her body a little (just a little!) in unpredictable ways. So, as she gives in to the rage it makes her look freakish and scary. Still mostly human though. But she's sort of addicted to the rage, likes it too much, and lets it take over more and more, and when it does it makes her look more freakish. This is me, as my compatriot Mister Bogart said, taking it more toward a dark horror concept rather than a superhero one. Or something along those lines anyway, maybe a bit of both. And she never really goes fully inhuman-looking in my concept, but she's afraid if she keeps giving into the rage it will reshape her in ways she can't predict and won't like. Maybe once, when she really gets pissed off, it does take her farther than she wants and it scares her. So from there it becomes a story about her learning to control her anger. You could look into therapeutic techniques for that and have her try some.
Xoic, raises a point I don't think he realized with the gradual transformation using her ability causes. That aspect becomes a limiting factor on the power. Mentally, this might mirror Ben Grimm of the fantastic four as he struggled with his tranformation.
There are some apsects of it I didn't mention, because I didn't want to lay it all out pre-formed. I want to leave it for @RosebySun to think about, but it's got a sort of built-in character arc and theme around which can be built a character web. It really lends itself to a story about unchecked growth and the frightening places it can lead to, and the need to (try to) put some kind of limits on it (if you can). And yeah, I was actually thinking somewhat about the Hulk, not so different from Ben Grimm. But more sort of re-imagined, by somebody like Cronenberg, to give it that surreal horror aspect that takes it well outside of the superhero realm. Or not, if that's not what she's looking for. All up to her of course.
We ask question and present ideas, with the intent of getting the author to think about the story in different ways. It is up to the author to decide what fits the vision of the story and what doesn't.
Ah ok, your suggestion sounds pretty good to be honest, since I also want to write something leaning towards the horror genre. You know what, I was thinking with the blood manipulation powers, why not I just make her more vampiric looking or somethimg similar for example unusual features more pronounced as time passes e.g paler skin, thin glowing mutated veins initially on her arms mutate and spread further, eyes and hair slightly change colour etc The anger and power aspect could be something that I could explore too