Cooper Seldon is an antagonist in Arrow. He was the boyfriend to Felicity Smoak during their college years together as well as being a member of the Hacktivists before getting arrested by the FBI for his computer crimes. Cooper is now the leader of a terrorist group called Brother Eye.
While attending the Michigan Institute of Technology, Cooper created a super virus program with his girlfriend Felicity and roommate Myron for their Hacktivists group. When the Hacktivists hacked into the Department of Education, Cooper attempted to get rid of all the students loans despite Felicity's protests. Cooper was then apprehended by the FBI afterwards and was assumed to have hung himself in prison. However Cooper was recruited by the NSA who were looking for people with his talents.
Cyber Attack on Starling City
Cooper used the super virus for a cyber attack on Starling City and attacked the Starling National Bank since he knew that a truck load of freshly printed cash would be sent to Starling City. Cooper abducted Felicity and her mother Donna and had Felicity hack into the GPS by defeating the encryption to make the truck drivers arrive at their location while using her mother as leverage. Felicity followed his orders since she had no choice in the matter. Cooper later left and robbed the truck drivers of the money that was being transported. Cooper later went back to his warehouse and tried to kill Felicity after he realized how Felicity used her mother's watch to contact someone. Fortunately, the Arrow arrived and stopped him. Cooper held Felicity hostage at gunpoint, however Felicity used her elbows to disarm and knock him out.
H.I.V.E.
Seldon is broken out of Iron Heights by Damien Darhk and employed by him during Operation Genesis. Seldon is tasked to regain control over Rubikon for H.I.V.E.. While Seldon hacks, Darhk asks him about Felicity. Cooper hijacks Felicity's system and boasts that he will soon have control over Rubikon. He also causes electrical systems in Felicity's flat to overload themselves and explode. However, Felicity does the same to him and the explosion of his monitor blasts Seldon through half the room.
Felicity finds a badly injured Seldon being forced to launch Rubicon after being shot with a bullet by Darhk who threatens to penetrate his spine with it should he disobey his orders. However, after being motivated to help save the world by Felicity he turns on Darhk but is promptly killed before he can stop the launches.
Trivia
He was inspired by the Big Bang Theory character Sheldon Cooper.