Weyoun is a Vorta clone serving the Dominion. Weyoun's earlier clones served the Female Changeling during the Dominion War. His last clone was believed to have been killed in 2375, however his line has survived into the 25th century.
Weyoun was first met by Starfleet in his 4th incarnation. He was tracking down rogue Jem'Hadar attempting to reactivate an Iconian Gateway on Vandros IV and suggested that the crew of the U.S.S. Defiant aid him in this task. He was killed by his own Jem'Hadar at the end of the mission.
Weyoun 5 became the liaison with the Cardassians on their entry to the Dominion in 2373. He served on Deep Space 9 during the Dominion occupation of it at the start of the Dominion War. He later died in a transporter accident orchestrated by Damar.
Weyoun 6 was found to be "defective" in the Founder's eyes, as he challenged the logic of the war and defected to serve Odo. Weyoun 7 was activated who pursued his predecessor. Weyoun 6 committed suicide in exchange for sparing Odo, but not before telling Odo that the Founders were dying. Weyoun 7 was killed later that same year by Worf who was held captive by the Dominion.
Weyoun 8 orchestrated the Dominion-Breen alliance and the sidelining of the Cardassians that led to their later revolt. As his first act of rebellion, the former puppet leader Damar destroyed Weyoun's cloning facilities as personal revenge on him. On the last day of the war, Weyoun 8 was killed by Elim Garak in the Dominion headquarters on Cardassia. His death was lamented by the Female Changeling, but Garak was happy to hear he had no more clones remaining.
While it was believed that Weyoun 8 was his last clone, in 2409 Weyoun 10 was active in the Dominion. The Female Changeling only discovered this following her release from Facility 4028 and was happy to receive him again. He would later directly serve the Female Changeling once more.
- “Operation Gamma”: The player meets Weyoun seeking aid removing Kar'ukan's forces from Deep Space Nine. He agrees, on the condition that the Female Changeling is released from captivity at Facility 4028.
- “Facility 4028”: Weyoun joins the player at Facility 4028 to pick up the Female Changeling, who is happy to see him. However, Kar'ukan arrives and goes rogue. Weyoun brings in Jem'Hadar to aid their escape.
- “Boldly They Rode”: Weyoun brings the Female Changeling to DS9, but Kar'ukan refuses to stand down. Weyoun and the Female Changeling suggest the player spacewalk across DS9.
- “Ceremony”: Weyoun conveys the player's promotion to First.
- “Turn the Tide”: Weyoun joins Odo's fleet on its way to Bajor.
- “Storm Clouds Gather”: Weyoun is present at the Alliance summit.
- “The Search”: At the end of the episode, Weyoun arrives to convey a message from the Female Changeling, and is overheard arguing with Loriss. He then chastises the player for interrupting a private conversation.
- “Doomed to Repeat”: Weyoun arrives with a contingent of Jem'Hadar at the ancient Dominion facility, killing a Hur'q as it was attempting to communicate with Odo and the player. He defends his actions by claiming that he acted to eliminate an enemy threatening a Founder.
- “Tenebris Torquent”: Weyoun arrives on Havas-Kul with Loriss and the Female Changeling. He then witnesses the Female Changeling's death at the hands of a mutant Hur'q. Grief-stricken by the loss of the Founder, he orders his Jem'Hadar to kill the player and their group, including Odo who he brands a traitor and blames for the Female Changeling's death. When the Jem'Hadar refuse to follow his order, he attempts to kill Odo himself but is stopped by Dukan'Rex. Odo then has Weyoun placed under arrest and beamed aboard his flagship.
- “Home”: Weyoun escapes prison and manages to get aboard a Hur'q dreadnought that is attacking Empersa. Still grieving for the loss of the Female Changeling, he destroys Ketracel samples that were to be used to pacify the Hur'q. He then orders Dukan'Rex to kill Dr. Bashir, but Rex refuses, instead killing Weyoun.
- Weyoun provides the sector space logs for the Gamma Quadrant.
- After players have completed "Operation Gamma", they can hail Weyoun's vessel in sector space near the Bajor system; players can ask him what the Dominion knows about the Iconians and inquire as to Odo's whereabouts.