Thaleste was born in Menzoberranzan as a member of a noble house. However, around 1373 DR, she angered her matron mother, who then poisoned Thaleste. She barely survived and escaped, going to Skullport in search of a cure.
During the patrol, while Cavatina was busy with a spellgaunt, Thaleste was attacked by an aranea cleric of Selvetarm. Cavatina however managed to arrive in time to save Thaleste's life.
Later, Thaleste went back to check the place of the attack and found a secret passage. She followed it without telling this to anyone, and while inside she was attacked and killed by a carrion crawler.