Ben Krullen was exposed to nuclear radiation while in the military. He would become a drifter after The Vietnam War. He would join the Council, a criminal group and his nuclear radiation would manifest and the Council's scientists would transform into a living human reactor. In his first appearance, Reactron took on the Doom Patrol while Supergirl was in her Linda Lee Danvers identity and therefore unable to help. After being outmatched by the Doom Patrol he disappears and Supergirl vows to challenge him if and when he returns. The next night Reactron turns up on Supergirl's university campus where he kills the security guard and finally meets Supergirl. This encounter would end with both of them battling over the city of Chicago. There was a huge atomic explosion which, Supergirl was able to contain. Reactron was believed to have overloaded and exploded over Chicago. He would join the Sgt. Rock led Suicide Squad. He was join a mission with Deadshot, Killer Frost, Major Disaster, and Blackstarr, another Supergirl villain. Reactron is encased in ice By Killer Frost during battle and shots from the enemy pierced the ice. The ice begins to melt and the rods that regulate his radiation are no longer working because he has succumbed to his shots. He begins to ooze green radiation into the ground once all the ice has melted around him.