Based on a certain thing that was dropped here a while ago, which, to be far, could have been just an independent artist's own creation, I have a suspicion that the "surprise" could be...
...Sarevok and whatever role he plays in the story. The "certain thing" would be a render of him an artist shared on the forum, with a detail of him shaving his goatee in the ~125 years that have passed between games. Given that the guy's been through Hells and back and has probably found a way to keep himself going even if Bhaal's essence was taken from him, I'd say that he's probably just as fit as he was in his twenties.
All speculation, obviously, but if it's indeed him, I really hope they got Kevin Michael Richardson on board. He has gotten older too, so his voice would fit an older Sarevok perfectly. And re-evoke BG1's narrator, Angry Druid, and Friendly Nobleman that he also voiced.
...or it could just be references to the Bhaalspawn and maybe even an ability to "customize" them in a KoTOR 2 fashion where you picked Revan's gender and Force side in a conversation early on. Could use Volo and his lack of credibility for that, so it doesn't turn into Jaheira and Minsc having memory issues about their famous lover/friend?
