Nestrix lived in the Raurin desert during her early years where she met her mate Tantlevgithus. At some point they moved to the Calim desert where she made a name for herself and acquired a sizable hoard by terrorizing caravans. The day the Spellplague struck on 29th Tarsakh, 1385 DR, a thief named Lyra sneaked into Nestrix's lair and attempted to steal a jeweled choker. Nestrix chased the thief into the desert and both were overcome by the blue flame of the spell storm. Lyra's body was transformed into that of a bronze dragon but the stolen choker choked her to death. Nestrix was turned into a human woman but many of Lyra's memories and possibly some of her consciousness were transferred to Nestrix.
Nestrix' lair and her eggs were destroyed by the Spellplague and her mate was killed. Since she had nothing tying her to the Calim any longer she wandered throughout Faerûn for many years. In 1478 DR she killed a wizard in Cormyr, possibly in self defense. Regardless, the War Wizards and the wizard's family put a bounty on her head and she escaped to Waterdeep.
She had heard rumors that the powerful Raptoran Sorceress Aundra Blacklock knew a ritual to reverse the effects of spellscars. She tried in vain to contact Aundra at the God Catcher, a tenement Aundra owned but was unsuccessful. A young apprentice wizard named Tennora Hedare who lived at the God Catcher took pity on Nestrix and arranged a meeting with Aundra. Nestrix explained her situation and Aundra agreed to turn Nestrix back into a dragon if she would steal back a magical mask from a shop in the Trades Ward.
Tennora and Nestrix broke into the shop and stole the mask. However, the shop belonged to a young green dragon named Andareunarthex (Dareun) and he was able to track Tennora back to her apartment. Even though he was weakened by Waterdeep's dragonward, he was able to overpower Tennora. Nestrix arrived during the middle of their battle and she was taken captive by Dareun and his minions who teleported her to a secret chamber in the sewers.
Tennora bargained for Nestrix's release in exchange for stealing the Song Dragon's choker for Dareun. The choker was a powerful magical item created for a Song dragon that came to Waterdeep's aid after the Spellplague. It allows dragons to escape the effects of the dragonward. Tennora sneaked into her former master's wizard academy, grabbed the choker, and returned it to Dereun's shop. At the shop, Dereun's head servant (lovac), Ferremo Magli took the choker and bound Tennora and threw her in the harbor. Tennora escaped and returned to her apartment where she and Veron Angalen, a bounty hunter who was tracking Nestrix, found an entrance to the sewers and eventually found Dereun's hideout.
While all this was going on, Dereun kidnapped the young son of one of Waterdeep's masked lords, Nazra Mrays in a plot to force Nazra to hand over the Dragonstaff of Ahghairon she held. Tennora freed Nestrix and killed several of Dereun's minions including Ferremo. However, Dereun escaped and teleported back to his shop with Nazra's son. Tennora, Veron and Nestrix found a teleportation item and teleported to the shop where they rescued Nazra's son.
They journeyed to Nazra's mansion and confronted Dereun, who intended to take the dragonstaff by force. In the battle that followed, Nestrix was gravely wounded but Dereun was driven off, presumably out of Waterdeep. Aundra Blacklock was apparently lying when she claimed to have the ability to transform Nestrix back to dragon form and Nestrix remained a human. However, Nazra touched Nestrix with the dragonstaff and named her a friend of Waterdeep although it's doubtful the staff had any real effect on Nestrix because the dragonward didn't bother Nestrix in her human form.
In her human form Nestrix appeared as a very tall woman with dark hair. Most people who saw her assumed she was Tethyrian. She doesn't have a spellscar on her body, rather her entire body is a spellscar.