In Smallville season 9 premiere, we were introduced to a John Corben who was investigating the recent monorail crash for a story. Apparently, he was brought into the Daily Planet as a replacement reporter for Clark Kent who was on indefinite family leave. But before Daily Planet, he had been doing field work in Afghanistan, and when he met Lois Lane, he expressed his desposition vigilantees, particular “The Blur”.
So, who is John Corben?
Well, in the comics (Silver Age of Metallo), John Corben was a journalist (and secretly a thief and murderer) who had just committed what he thought was the perfect murder. While fleeing from the scene of the crime, he suffered a near-fatal accident that mangled his body beyond repair. However, elderly scientist Professor Vale happened to come upon him, and used his scientific skill to transfer Corben’s brain into a robotic body covered by a fleshlike artificial skin. However, Corben discovered that his power source, a capsule of uranium, would only last a day, but was told by Vale that kryptonite would provide him an indefinite power supply.
In the mythology, he entered Superman’s life when got a job at the Daily Planet as a journalist and pursued a romantic relationship with Lois. Lois had brief feelings for him for that she claimed he resembled Superman, this of course really bothered Clark. At the same time Corben turned his attention towards Superman, the one person who might expose his criminal deeds. He set traps and he used his power to try to eliminate him. Although almost successful various times, Superman prevailed.
Currently in the comic books, Metallo is still a threat to Superman and continues to upgrade his robotic body for criminal mayhem.