A lonely research scientist, Doctor Simon Ecks discovered that the energy auras that surround eery human being could be amplified, strengthened and given enormous powers and enabled to function separately from the host body.

Without waiting to test his invention, Ecks used it to create an energy duplicate of himself that he called Double X, and his fragile mind unhinged by his energy duplicate, Ecks and Double X embarked upon a crime spree, using Double X's powers to oercome all opposition.

Eventually defeated by Batman and Robin, who destroyed Double X by destroying the machine that created him, Ecks was committed to Arkham Asylum. Months later Ecks escaped and using a previously hidden duplicate of his first machine, he recreated Double X only to be defeated by Batman again. With Ecks once more in custody and hid duplicate machine destroyed, it appeared the threat he posed was over.

However, Double X was sleeping in Ecks' body, and years later when he realised this was the case, Ecks plugged his finger into an electrical socket, absorbing enough energy to free Double X once again. This time it took both Batman and Superman to overcome him. Double X later reappeared and teamed up with the Rainbow Raider, but the duo were defeated by Batman and the Flash.