Okay .. I think I won't ever find that story again ,but here goes nothing. 

It is a supernatural fic , I think exo was in it (not sure though) but the only scene I clearly remember is a fight ,where all the guys are already on the ground but the girl can somehow resist the evil character and somehow with her mind kills all the bad people around her, to save them all. The scene was pretty far along the end I think and the girl is a vampire .. I think . She was saying something like "who do you think I am"....maybe ....I know it really isn't much, but if it sounds just slightly familiar ,just give me a link to whatever you think it is please :( 

Although I'm pretty sure with my luck ,that story just doesn't exist anymore :D