- 2371: The yet to be named Dukan'Rex is found by Quark as a child in some salvage he has purchased, and is later cared for by Doctor Julian Bashir. The child's heritage is unknown, but after a period of rapid maturation, the crew soon realise that the child is a Jem'Hadar. He is taken into Odo's care, given the boy's natural deference to his species. However, his violent instincts cannot easily be contained and Starfleet Security become interested in studying him. Eventually, Benjamin Sisko and Odo allow the boy to flee the station and return to the Dominion before Starfleet can arrive. (The Abandoned)
- “The Search”: Dominion players are ordered by Dukan'Rex to join a Dominion-Alliance task force in the Dosi System.
- “Doomed to Repeat”: Dominion players are ordered by Dukan'Rex to join Odo in his investigation of the Masan System.
Engineered for War
- “Hunt”: Dukan'Rex oversees the player's exercise on becoming First.
- “Ceremony”: Dukan'Rex is present during the player's promotion to First.
- “Turn the Tide”: Dukan'Rex joins the player in Odo's fleet to defend Bajor.
- During each of the missions in Gamma Quadrant episode arc, Gamma Recruits are contacted by Dukan'Rex.
- “Storm Clouds Gather”: Dukan'Rex is present at the Alliance summit on DS9.
- “The Search”: Dukan'Rex joins the Dominion-Alliance team investigating the Hur'q in the outer-Dominion planets.
- “Doomed to Repeat”: Dukan'Rex escorts Odo in the investigation of the Ancient Dominion Station.
- “Tenebris Torquent”: Dukan'Rex forms part of the team investigating Havas-Kul.
- “Home”: During the defense of the Founders' Homeworld, Dukan'Rex and Dr. Julian Bashir board a Hur'q capital vessel to provide them with a cure to their mental situation. However, Weyoun vaporizes the package and orders Dukan'Rex to defend him, who shoots him instead. Afterwards, Dukan'Rex sacrifices himself by providing the Hur'q with the knowledge of Ketracel White contained in his body.
- "Reunion": Years after leaving Odo and returning to the Dominion, the soldier now known as Dukan'Rex reunites with the founder during a mission on Stakoron.
- Dukan'Rex has a personal ship which is simply marked as Dukan'Rex to the player.
- For Jem'Hadar and players who have completed “The Renegade's Regret” but have not yet played “Home”, Dukan'Rex can be found with Odo on Deep Space 9 in the Security Office.
- Along with Alexander Rozhenko, Ajur, Boratus, Gaul, Golin Shel-la, Kahless, and Taris, Dukan'Rex is one of the very few canon characters to actually die in Star Trek Online.