Kryptonite Man
The Kryptonite Man
There have been two separate individuals that Superman has encountered in the course of his adventures who have used the name The Kryptonite Man.
Version One
The first of these individuals begins his career as the Kryptonite Kid, be-devilling Superboy. A telepathic juvenile delinquent from the planet Blor, he has the power of Green Kryptonite and is the sworn enemy of Superboy. In September 1960, the unnamed kid and his dog pass through a green cloud in space, both gaining an emerald hue and the attributes of Kryptonite, which is deadly to Superboy and all survivors of Krypton. The duo then journey to Earth and, calling themselves the Kryptonite Kid and the Kryptonite Dog, use their Midas-like ability to transform everyday objects into Kryptonite, threatening the lives of Superboy and Krypto--who are only saved at the last minute by the 5th-Dimensional magic of Mr. Mxyzptlk (SB No. 83/1: "The Dreams of Doom").
Years later, the villain returns to threaten the Man of Tomorrow as an adult, now calling himself the Kryptonite Man (S No. 299, May 1976: "The Double-or-Nothing Life of Superman!").
Version Two
The second being to use the name the Kryptonite Man had been the ruler of a race of humanoids who inhabited Krypton eons before Superman's ancestors. When a nearby cosmic body threatened life on Krypton, the second Kryptonite Man, whose real name is never given, sends all of his people into stasis deep underground, while he himself remains on the highest mountain peek, to act as their guardian. He is then placed in suspended animation for what is to be 20 years, at which time, he will awaken to determine if the planet is habitable once again. For some unknown reason, the machinery fails, and the unnamed ruler slept for over a thousand years. Unfortunately, the very day he awoke, is the day Krypton exploded.
The mountain that the unnamed ruler's observatory was on, was sent into space, and somehow, the king was able to feed off of the kryptonite radiation the mountain produced. He eventually became dependent upon these energies to sustain his life at all times, weakening outside of its influence.
The Kryptonite Man blames the human inhabitants (Superman's race; see Kryptonian) with the death of the planet Krypton, never realizing that it was a natural disaster. Eventually, after the kryptonite radiation of the mountain began to fade, the Kryptonite Man encounters a race known as the Seeders. For unknown reasons, the ships of this race produced radiation similar enough to kryptonite radiation, that Kryptonite Man could feed off of it, and survive.
The Kryptonite Man discovered the existence of human Kryptonians on Earth, and stealing a Seeder ship, traveled there to confront, and kill them. He attacks Superman and Supergirl, but their battle is interrupted by the Seeders, who have taken offense to the theft of their spacecraft. Eventually, the Kryptonite Man sacrifices himself to prevent the Seeders from destroying the Earth in their zeal to kill him, taking the Seeders with him (S No. 397, Jul 1984: "The Born-Again Kryptonite Man!").
