Nefara, the Lich Queen, is an undead Shuriman princess infected by the Void.
Nefara was a contemporary of Xerath. A princess in one of the empire's territories, she was also a gifted mage, and he may have killed her when she began to suspect his plans for manipulating Azir's Ascensio n.
During the Hextech Revolution, scouts from Bandle City inadvertently released Nefara from the Floating Pyramid of Akhtal, where she had been entombed.
She raised an undead Shuriman army that attacked Bandle City, and likely would have destroyed the yordle homeland if Demacia, Piltover, and Zaun had not come to their aid.