Kys'sea is the daughter Nyo'ka, a Vloz'ress nether summoner. She was studying abroad in Nuqrah'shareh, before returning to Vloz'ress lands.
Biography - Arc I
While home in the Vloz'ress fortress, Kiel'ndia staged her bid for control of the clan. Following an assassination attempt that Kiel blamed on Nyo'ka, Tamiir and Kys'sea cowered around their mother desperately when Kiel came to execute her. Touched, Kiel decided to spare Nyo'ka. 
Biography - Arc II
Tamiir and Kys'sea were studying in Nuqrah'shareh when the civil war broke out. A number of revolting commoners found them with their classmates and attacked. Using a combination of mana arts and physical attacks, the children defended themselves until their teacher, Sandaur, could rescue them. They were later taken hostage by the revolutionists, but were freed when the loyalist forces regained control.
This article reflects events up to Chapter 40.