Pre-Crisis Benjamin Krullen is a sergeant serving in the US Army during the
Vietnam War, alongside
Joshua Clay. When Krullen massacres the inhabitants of a Vietnamese village, the shock triggers the activation of Clay's
metahuman powers. Clay seemingly destroys Krullen with his energy blasts, then goes AWOL. Krullen, instead of being killed, is transformed into a being capable of generating radioactive energy and concussive blasts. Calling himself Reactron, the Living Reactor, he surfaces years later and attacks the
Doom Patrol, then later fights
Supergirl.
Post-Crisis Reactron's origin and background are altered following the 1985
Crisis on Infinite Earths continuity reboot. he faces the Doom Patrol and
Power Girl in his first appearance. Most of his pre-
Crisis continuity seems intact, but it is now said that his previous battles involved Power Girl instead of Supergirl. Seemingly destroyed after overloading on
Negative Woman's energy, Reactron resurfaces unharmed as a member of the
Suicide Squad. Reactron reappears in the
Superman: New Krypton storyline with a new costume and abilities. Recruited by
Sam Lane as part of
Project 7734, Reactron is equipped with a heart made of gold
kryptonite and partnered with
Metallo. Reactron and Metallo attack the city of
New Krypton, where Reactron kills
Zor-El, the father of Supergirl. As part of his participation in Project 7734,
Lex Luthor sends a robot double of himself with
Brainiac on a mission to attack New Krypton, a new planet in Earth's solar system populated by the survivors of the
Kryptonian city of
Kandor. While there, the Luthor robot tampers with Reactron's body chemistry. Shortly afterward, Reactron kills himself, causing a chain reaction that destroys New Krypton and kills all but a handful of its inhabitants. ==Powers and abilities==