Leonard "Len" Snart was a criminal who wanted a chance to get rid of the Flash. Seeing an article about a weapon that might disrupt the Flash's speed, Snart made a gun and exposed it to the radiation. However, instead of slowing the Flash down, the gun could freeze anything to absolute zero. Calling himself Captain Cold, Snart started out on a criminal career. He is considered to be the arch-nemesis of both Barry Allen and Wally West, and the leader of the Rogues. Known for being a sympathetic villain, Cold has a sense of honor. Cold has strict rules on how the Rogues should act, such as no drugs and to not kill unless they have to. Also has a sense of loyalty to his team and watches out for them.