I don't think it is possible, I've tried before. If she goes on the quest (and I think she eventually will no matter what), she doesn't come back. In my experience, anyway.
Here's another question about that same lady: is she always represented by the same portrait? She always has been in all my games where she appears, but now I've started a game and the 'usual' portrait has appeared as a different Vingan... will Kallyr ever appear, and will she use a different portrait?
Wulf
Powered by hypermail