Viconia was from a Drow House of high standing, but was forced to flee to the surface after she'd refused to perform to sacrifice an infant child. As a result of this act, her family was disgraced, and her brother, who had stood up for her, was turned into a drider as punishment. Shar, the Goddess of Loss and Darkness, granted her powers in the surface world, but agents of Lolth continue to search for Viconia, intending to destroy her.
Baldur's Gate