I haven't play DoS 2 yet, just watched a few videos, still I agree with Piff, Astarion looks very much like Sebille (and a lot of other rogue characters, sure, but still once you noticed it it's a shame). I really enjoy Astarion character and I think (hope) that he could have a very interesting development regarding the player choices, but, once you have a made the parallel with Sebille, I don't know, it kind of "kills te mood". I just really hope that Larian is aware of those likenesses and that they prepare something (a little) different for Astarion.
Still, I won't complain about stereotypical characters as long as they have depth, and, as for now, all our companions have in-depth potential. So, wait and see!
