Not meaning to be rude or confrontational or challenging but how does Katarina, a four and a half foot tall girl even draw, let alone murder people with a recurve bow? I mean this as an honest question, not in any way saying that I don't like the character. A skilled archer draws with one hundred pounds of force. The average draw weight for such a child is only 10-15 pounds and while I wouldn't want to get in front of any bow, this arrow would be moving almost ten times slower, easily stopped by really weak armour and also slow enough to easily dodge or possibly even catch! Also, it is said that she studied magic for several years? What sort? 

Honestly though, I do like the murderous tiny girl concept. One possible explanation for her ability that comes to mind is that maybe Katarina somehow uses magic on her bow or casts some sort of spell to help her become stronger, enough to draw more weight on the bow making her a more deadly archer while still remaining small? Maybe she possesses a special magic bow with a history of its own?

On a secondary note, this is turning into an interesting group. So far they're all con-artists, thieves, assassins and the like. Not your typical heroic fare.