Well the idea I have is that Taorii is a refugee, from some island off the coast of Chult (we're going with the Forgotten Realms setting, right?) - the island was invaded and enslaved by someone (which would be her favored enemy) and she was part of a small few who managed to escape and ended up scattered around Toril. Your classic sort of paradise lost thing  ;D As for who... I dunno, what's the new version of marauding orc hordes in this world? is it still marauding orc hordes? In the time since the old races died off, maybe hte Dinosaurs of Chult gained intelligence? Maybe it was a dragon? I dunno