Oh I see. Well, the character doesn't have to be a dragonslayer I suppose. 
[hider=Bit More Info on her]The premise for her was that she was found by a few members of her current guild, frozen in time in a block of ice on top of Mt. Hakobe. (Originally the idea was that the winter dragon, Glacia, froze her there because she knew if she suddenly disappeared my character would search non stop for her, but again it can be changed.) She's comically deadpan in contrast to her guild members, making them think she's always sad or unamused but she's honestly very happy to be with others because she has never had a real friend before. (Face snapping every time she tries to smile, attempting to laugh and her jaw freezing, and other funny stuff will ensue because of this.)[/hider]

She could just be an oddly powerful ice magic user, but the whole point of her character is that she was isolated for years in a block of ice and is out of touch with the world. I don't know why or how anything else would cause that...