Almost nothing is known about Epsilon's childhood, however one thing is for sure, it was one with a lot of problems.
Ever since he was a little boy, Epsilon was a ward of The Department of Extranormal Operations's orphanage, thanks to his great intellect. This orphanage was top secret, and was made to take care of all young metahumans.
Although it was never fully explained what powers Epsilon has, it was shown that he had a variety of powers, including super strength, the ability to fly, immunity to magic and enhanced durability.
After Epsilon sometimes showed a psychotic personality, the D.E.O decided that it would be better to keep an eye on him even after he left the orphanage when he turned 18.
Along with his lover Theta, Epsilon worked for a mysterious benefactor. He was hired by that benefactor to join the Titans and destroy them from within. Soon after he was hired he made an appearance in New York disguised as a superhero trying to get recruited by the Titans.
It was when the rest of the orphans from the D.E.O. saw in the news that both the Titans and Epsilon were working together, that they decided to escape the orphanage.
There was one D.E.O. orphan named Kevin Tanake, who had the power to project his mind into another person's body, he used that ability to seize Epsilon's body, at the same time the rest of the orphans used that opportunity to escape the orphanage in an attempt to find the Titans and ask for their help. The only problem with Kevin's idea was that it caused the psycho teen to change personalities and moods very quickly, sometimes he was gentle and other times he was rude.
Tough Native American D.E.O. Agent Dakota Jamison first came into conflict with the Titans over the mysterious Epsilon. The Titans fended off the D.E.O. and granted Epsilon safe haven in the Titans Tower. At this point, Nightwing and Dakota Jamison secretly began to build a case against the suspicious Epsilon.
When Epsilon secretly met with Theta at a posh Manhattan hotel, he began to shift in personality from Epsilon to Kevin and back again, leaving Theta baffled at her lover's strange behavior. Meanwhile, Argent began to develop an attraction to Epsilon. Kevin was a child in an adult body and often felt awkward. Kevin, in the guise of Epsilon, gave into temptation and began a romance with Argent.
Powers & Abilities
Epsilon's powers have yet to be fully catalogued; he appears to possess great strength, incredible durability, concussive energy blasts and the power of flight. He also seems immune to magic, as Dark Angel's spell and Tempest's eye beams have no effect on him.
Theta appears to share many of Epsilon's meta-abilities, including great strength, incredible durability, concussive energy blasts and the power of flight.