Member of the Lucian Alliance, a criminal organization based in the Milky Way Galaxy. Simeon was on the team that infiltrated the Ancient ship Destiny under the command of Kiva, and one of the few survivors of the failed incursion who was allowed to remain on board.
Simeon was reserved and calculating, feeding Earth misinformation while Varro and other Alliance members cooperated. He was difficult for both Varro and Colonel Everett Young to manage, making lewd remarks or hostile gestures at other crew members.
Homeworld Command officials eventually discovered that Simeon was a member of the clan planning a direct attack on Earth -- as was Ginn. When he learned that she was using the communication stones to be debriefed on Earth, Simeon murdered both her and Amanda Perry, the scientist to whom she was connected. He escaped the ship through the Stargate with stolen ordinance and a hostage, evading capture by Destiny's search parties for several hours.
Simeon was eventually tracked down by Nicholas Rush, a close friend of Dr. Perry, who shot him dead in the desert -- even though he was offering to give information about the attack on Earth in exchange for his life.
Intervention - Simeon participates in the Alliance's attempt to take over Destiny, and questions Telford about what happened when he and Kiva were shot.
Aftermath - Simeon is one of a handful of Alliance survivors allowed to remain on Destiny, the rest of them left behind to fend for themselves on an uninhabited planet.
Awakening - Simeon tests his boundaries with T.J. Johansen during a medical check-up, and is quickly put in his place.
Pathogen - Simeon tells Varro that he has been giving Earth misinformation about the Alliance, and is stunned when Varro tells him the rest of them are being truthful -- and that he must do the same.
The Greater Good - Simeon goes after Ginn after he learns that she is going to be debriefed about the impending Lucian Alliance attack on Earth.
Malice - After murdering both Ginn and the scientist with whom she had traded bodies, Simeon flees through the Stargate and eludes Destiny hunting parties -- before being caught and shot dead by a vengeful Nicholas Rush.