The Imperial Guardsman have served in the Imperial military since shortly after the Battle of Endor. When James Ardin reinstituted the Royal Guard program Valis Thorn volunteered and was quickly found suitable for the task. Like most Guardsmen he is deadly with his force pike, and a sharpshooter with his pistol.
However, what sets him apart was his special operations experience before joining the Guardsman program.
He served as James Ardin's guard and was present during the assassination of the Regent. He was the only guard to survive the ideal and continue his duties under Emperor Damascus. He served Damascus loyally until it was revealed to him that the former Intelligence Director had a hand in Ardin's murder, and a clone of the former Regent was activated. When the cloned James Ardin confronted Damascus, he turned on the other Royal guards, killing them before firing on the Emperor. Damascus absorbed his blaster fire but it gave Delth the time he needed to kill the Emperor.
Valis left the guardsman program and served as a special operations officer under Delth Ardin. He followed Delth on his mission against the Xen'Chi, and through a twist of fate wound up on the Cleansing. He witnessed unthinkable things while on that ship with the mercenary Consecro, fighting not only the Xen'Chi but also the haunted spirits controlled by Damascus. After the once-dead Emperor took control of the ship he reluctantly joined him to defeat GAIT and the Xen'Chi. He was eventually mortally wounded by a Xen'Chi in a battle, but was brought off the station. Valis eventually died on the Insidious, but not until after telling Delth exactly what he would have to face on the Cleansing when he fought GAIT.