Valen was a vampire who worked for Bodhi.
Baldur's Gate IIEdit
In Chapter 2, when you have collected 15,000 gp, Valen will appear and ask you to meet her mistress, Bodhi.
If you sided with the Shadow Thieves, when you arrive in Brynnlaw, Valen and two other vampires will attack.
Valen will be in the lower crypts defending Bodhi's inner sanctum in Chapter 6.