Illorus was a young female who underwent training to become an Imperial cadet at the Academy for Young Imperials. This academy was located on the world of Lothal, and her training took place approximately five standard years prior to the Battle of Yavin. While in training, she belonged to the all-female Unit Forn alongside three additional trainees. However, she faced setbacks and was ultimately removed from the Imperial academy after twice failing to complete objectives in a combat training drill. Later, Commandant Cumberlayne Aresko asked about Illorus's fate and was told by Sergeant Currahee that she had been dismissed. Following this, a student from another academy on Lothal took her spot in Unit Forn.
Illorus's initial mention occurred in Servants of the Empire: Rebel in the Ranks, a 2015 novel authored by Jason Fry. Although several cadets from Unit Forn are shown in the book, the names of these girls are never given. Furthermore, because the exact time of Illorus's dismissal is not specified, it is uncertain if any of the cadets depicted in the book are meant to represent her.