Theromos was young when the Nerazim's studying of the Void had only just begun, and partnered up with a fellow student, an ambitious female named Naraza. She convinced him to perform a ritual that would combine the two of them into a powerful, permanent dark archon. He agreed, but was not strong enough to go through with the ritual. Naraza ignored his pleas to stop, and was consumed by the Void. This traumatic event made him pledge to only teach others in the use of Void powers, and not wield them himself. He taught many students, who spoke highly of their teacher, and how his training changed their lives.
Lens of the VoidEdit
Centuries later, after the Khalai's exile from Aiur, Theromos trained young Nerazim in the handling of the main weapon aboard the void ray Purity of Form, a new type of warship that combined the energies of the Khala and the Void into a powerful prismatic beam. This was done at the request of the Hierarchy. Theromos refused to become a Void lens himself, and would only teach other Nerazim in the handling of the beam weapon. One of his students, Althai, was killed when he tried to wield more power than he could handle during a battle against the zerg. This caused tension between Theromos and the ship's commander, the Khalai Feranon.
His next student, a female named Sharas, proved more capable in handling the dangerous energies, and Theromos eventually told her the story of Naraza. At that point, they were interrupted by a zerg attack on their base. Sharas was forced to use the full power of the void ray, and only survived because Theromos linked with her to stabilize her and give the prismatic beam weapon the power it needed.
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 his latest pupil's training was complete.