A test pilot, who piloted his plane through some strange energy belts, finding when he landed that he glowed with negative radiation. He was held in isolation until Niles Caulder was able to come up with a solution in the form of radiation-proof bandages. Trainor discovered that the negative energy inside him could be projected for around a minute, performing great feats - using this ability he joined Caulder's Doom Patrol until the team was destroyed, at which point he lost the energy to one Valentina Vostok.
Years later, Trainor wanted the energy back. He got it - and then some. It transpired that the negative energy had some form of sentience, or at least a plan, and it fused Trainor with his female doctor, creating possibly the first hermaphroditic super-hero, Rebis.