Glessin joined the Guard where he trained to be a medic. While doing so, he met another Cardassian who was a medic on Terok Nor. Glessin had finished his mandatory tour in the Guard by the 2370s and began to study biology under a person who was actually a member of the Obsidian Order. The teacher recommended him to the Order, who assigned him to the Keldon class starship Danasket. The ship was stationed in the Orias system for the joint Obsidian Order/Tal Shiar attack on the Founders' homeworld in 2371.