Some time after the khalai's exile from Aiur, she was brought aboard the void ray Purity of Form to be trained in the handling of the ship's primary weapon, a prismatic beam fueled by the energy of both the Void and the Khala. Her teacher was the ancient dark templar Theromos, who had just lost his previous student, Althai, during a battle against the zerg.
Sharas proved very capable of handling the dangerous energies, and Theromos eventually told her the story of Naraza, a friend of his who was killed centuries earlier when trying to handle the full power of the Void. He also tells Sharas that she reminds him of his long-dead friend.
At that point, teacher and student were interrupted by a zerg attack on their base. Sharas was forced to bring the prismatic beam to full power, and only surivived because Theromos linked with her to stabilize her and give the prismatic beam weapon the power it needed. During this link, she was tempted to give herself over to the Void, but the older protoss was able to convince her to let it go.
After this experience, Theromos realized that he could no longer hide behind his ancient grief. He thanked Sharas for the lesson she taught him, and offered to become the Purity of Form's permanent "void lens" once Sharas' training was completed.