Baldur's Gate II: Throne of BhaalEdit
Alianna appears as a ghost in the Pocket Plane, alongside the ghost of Gorion, after the player kills Yaga-Shura. She reveals her true identity as a priestess of Bhaal, how she came to be the mother of a Bhaalspawn and how Gorion killed her.
This means that Gorion lied in the letter the player finds in the first game, where he stated that she died in childbirth.
Either the information given is a lie or it creates a plot-hole. Her statement implies that she was still alive during the Time of Troubles and that she gave birth and died around the same time. That would mean the protagonist is just about ten years old during the time the games take place, which they are clearly not.