Feranon had a stellar service record. At some point he visited a xel'naga temple.
Feranon considered his service record to be part of the reason (the other part being his openness to the Nerazim) why the Hierarchy put him in command of the Purity of Form, one of the first void rays jointly built by Khalai and Nerazim engineers. He was impressed with both the properties of the ship, as well as its aesthetics.
He commanded the ship during several battles against the zerg swarm, during one of which he told the ship's void lens, the young Dark Templar Althai, to draw more power from the Void than he could handle, killing Althai. This caused some tension between the commander and the void lens' teacher, the Nerazim Elder Theromos, who had advised against it.
A new student, Sharas, was brought aboard, and proved more equal to the task. However, she too was in danger of losing herself in the Void during a battle against a zerg hive, when Feranon again demanded more power for the main weapon. Theromos had to link his powers with Sharas's, and the Purity of Form prevailed.
The elder later visited Feranon in his quarters and offered to become the ship's permanent void lens once Sharas's training was completed. Their relationship seemed to become somewhat more friendly at this point.