Well with her past intentionally shrouded in mystery there doesn't seem like a whole lot of room to work with. I mean how long has she been around? Would there even have been time for her to make enemies with someone and then reconcile? Or to go on previous missions together? Or to get close enough to hold a secret? When there's no real history on her background it's hard to kinda piece these things in, especially when the majority of her bonds are event based.