so i'm basing my character's powers off a manga called RE:monster (check it out its pretty cool) in which the main character is able to eat anything and gain powers from it. Granted i'm reducing her strength seeing as in the manga the main character becomes unstoppable after a couple meals. As for the blood magic specifically i want her to have an ability that involves using her injuries. I'm not sure what yet.
Oh, indeed he does become unstoppable. It's practically skill stealing.
How about you make her an Avenger, a class that gets stronger the more injuries they receive. To match with it her ability to consume things could be limited to things within a limited group which is decided through the first thing she uses it on. E.g. she eats the meat from a Lion and can continue to get stronger from eating other animals in the feline family. She could also gain more beastly traits from it, again depending on what animal she ate.
Similar to Lycanthropy mentioned above.
Alternately, she could just take a portion of the highest stat granted by whatever she eats. E.g. Eating a bear would probably increase her strength.
of course, there'd have to be some form of limit to this else she'd grow without limits.
I believe that once the characters really get into traveling, then my own Oc would start interacting with them.