Roy came into a large inheritance and used the money to develop radiation-based super powers so he could join the Legion Of Super-Heroes. However, he did not have great control of his power and almost hurt the Legionnaires. His application was not helped by the telepathic probe Saturn Girl performed on Roy's mind, and his inner desires so horrified her she couldn't sleep for two nights. Due to that, he was rejected.
Radiation Roy created by Jerry Siegel and John Forte
Angry and bitter, Roy joined the Legion of Super-Villains and periodically fought against the Legion. When he joined the L.S.V., he started a relationship with Spider Girl, but this ended. During his future appearances, it appeared his radiation powers were taking a toll on him, as he soon lost all his hair.
Threeboot / Earth-Prime
Radiation Roy briefly appears in the "Threeboot" Legion continuity, as an angry teenager who lashes out at Science Police officers with gamma radiation, while someone in the crowd yells out "Roy, No!". He is quickly stopped by Cosmic Boy and Supergirl
Retroboot / New Earth
When his body was so badly ravaged with radiation poisoning, losing most of his teeth and growing hideous, pus-filled tumors, Roy started wearing a red containment suit. He later joined up with other Earth-born rejects of the Legion, led by Kirt Niedrigh, now calling himself Earth-Man. Using a crystal tablet Kirt unearthed in the Arctic, their group, calling themselves the Justice League of Earth, started preaching that Superman was actually a native of Earth, and that his Kryptonian heritage were lies the Legion spread to plan a wide-spread invasion of Earth. Hailed as heroes and adored by children, Roy and the Justice League continued spreading their lies as they hunted down whatever aliens, and Legionnaires, were still on Earth. Roy also tried to rekindle his relationship with Spider Girl, but she coldly rebuffed him. It wasn't long before the League was exposed by the combined might of Superman, the Legion, and the Legion of Substitute-Heroes, and Roy and the others were sent to the prison planet Takron-Galtos.
Major Story Arcs
Retroboot / New Earth
Superboy-Prime and Legion of Super-Villains
Roy and the League returned in Final Crisis: Legion of 3 Worlds, when Superboy-Prime freed all the inmates of Takron-Galtos and set the planet's surface on fire. The J.L.E. decided to join Prime's new Legion of Super-Villains, alongside the old members, the Fatal Five, and just about every other villain the Legion ever fought. During the attack on the United Planets, Roy killed Myg, formerly the second Karate Kid, of Lythyl, before he was electrocuted by Lightning Lad.
Powers & Abilities
Roy is able to unleash a potent blast of radiation. This radiation is not immediately lethal, but it is potent enough to affect those that are ordinarily immune to such effects because they are desolid.