The Kryptonite Man is the name of several supervillain who appears in stories published by DC Comics. The character first appeared as Kryptonite Kid in Superboy #83 (Sep. 1960), and as Kryptonite Man in Superman #299 (May 1976).
The original Kryptonite Man started out as a teen-age alien criminal, who flew in space through a green kryptonite cloud and became imbued with the properties of Kryptonite. This incarnation is most well known pre-Crisis on Infinite Earths from his appearance and death in the non-continuity story Superman: Whatever Happened to the Man of Tomorrow?.
A second Kryptonite Man appeared in Superman #397. He had been the ruler of a race of humanoids who inhabited Krypton eons before Superman's ancestors. When a nearby cosmic body threatens 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 peak, to act as 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 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 is sent into space. Somehow, the king is 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. This second Kryptonite Man blames the human inhabitants (Superman's race) with the death of Krypton, never realising 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 produce radiation similar enough to Kryptonite radiation, that Kryptonite Man could feed off of it, and survive. Kryptonite Man discovers the existence of human Kryptonians on Earth, and stealing a Seeder ship, travels there to confront, and kill them. Kryptonite Man attacks Superman, but their battle was interrupted by the Seeders, who took offense to Kryptonite Man's theft.
In the post-Crisis era, the Kryptonite Man appears in Superman (Vol. 2) #43 as a green-skinned clone of Superman, grown by the scientific spies Simyan and Mokkari.
Read more about Kryptonite Man at Wikipedia ...
Official Site: DC Comics
Links: Wikipedia DC Database Project Superman Homepage