Illiya Tal'Dorei

 is the daughter of Sovereign Uriel Tal'Dorei III and Salda Tal'Dorei. As an NPC, Illiya is played by Matthew Mercer.

Background
Shortly before Vox Machina arrived in Emon for the first time, there was an attempted assassination on Uriel's family, which was thwarted by General Krieg. Following the attempt on their lives, the royal family grew strange and withdrawn, keeping Uriel away from the Council of Tal'Dorei.

After being barred entry to the palace for seven days, Allura Vysoren took Vox Machina to her home, the Ivory Tower, where she and Keyleth scried on the Palace. Their vision revealed that Illiya, her mother, and her siblings were all under the influence of a demonic force and had been addling the mind of Uriel to use him as a mouthpiece for their plot.