Frenna will be a partner for the Changeling, who took her when she was young from the north after killing her family. Unknown to herself that he had done so.
It was likely for the best, for her family were cannibals who eat human and monster alike. Even the Children of the Forest were not able to escape their hungers and she was born with their stolen blood running through her, an excuse to explain where Wood Elves come from, even if she might be the only one still living.
Too young for the Changeling to feel comfortable killing her after offing her family he took her on as a rather troublesome daughter, especially when it turned out the Old Magic ran strong in her blood. Frenna is now all grown up although far from fully civilized. Even if you only lived off human flesh as a child it leaves you with an outlook on the world that's considerably different to the norm. Frenna's very religious when it come to the Old Gods, who she feels have a plan for her they'll reveal someday, if that's a good or bad thing she couldn't say.
Exotic in look, she tends to gravitate towards similar freaks who don't mind so much though she knows even they won't be accepting of her past so she's got good at just not talking about it. When mixing in better company her elven and exotic looks can help her pass, providing she plays it carefully and doesn't try to punch above her station. Which is difficult, because it comes to the Game she is singularly terrible at it, she likes people plain spoken, honest and passionate. All things in short supply in the more hallowed halls of Kings Landing.