The 1st Metallo:
Metallo first appeared in the story: "Man of Steel versus Man of Metal."This story was Pre-Crisis, and was considered to have taken place on Earth-2. The first version of Metallo, originally spelled "Metalo," was a scientist named George Grant. Grant had a powered suit of armor, and during a second encounter with Kal-L, had also taken a serum to increase his strength to super human levels. During their battle, Grant fired a special beam at Superman, that dramatically decreased the Man of Steel's power. Superman recovered his power through a strict exercise regiment, and was able to easily beat Grant.
The 2nd Metallo:
Pre- Crisis, John Corben became the first Metallo. He was a shifty reporter who, after a near fatal car accident, was turned into a cyborg by Dr. Vale. His failing heart was replaced with an artificial heart made of Uranium, and his skin with artificial skin. After this, Vale suffered a stroke.
The Uranium depleted after a day, leaving Corben feeling lethargic. In order to restore his heart, he needed to steal more Uranium. Corben got a job at the Daily Planet, and began courting Lois Lane due to his resemblance to Superman. During this time, Vale discovered Kryptonite could be used as a replacement for the Uranium. Metallo decided to steal some Kryptonite on loan to a local museum. After finding out that Kryptonite is lethal to Superman, and fearing retalliation from Suprman for his crime, he decided to kill him. He laid a trap for Sueprman, and chased him back to Lois Lane's apartment. At this point, Metallo died of a heart attack- the rock had been a fake, painted green.
John Corben was a small-time con man and murderer that was mangled in a car accident. Corben's body was crushed, and he would have died within minutes, had the wreck not been found by Professor Emmett Vale. Vale put Corben's brain into a robotic body that was covered in fake flesh and it was powered by a chunk of Kryptonite. Vale was an eccentric scientist who had spent much of his life scanning the skies for signs of alien invaders. Vale misled Corben and told him that the Kryptonians were set to invade the planet, so he had to fight Superman.
Instead, John then snapped Vale's neck. Later Corben, now calling himself Metallo, finally did fight Superman. Lex Luthor once captured Metallo hoping to remove his chunk of Kryptonite to use for his own purposes. Metallo was able to escape using a back up power cell. He sold his soul to the demon Neron for more power and soon after, joined forces with Braniac 13.
Corben's metallic body grew to giant proportions after absorbing Metropolis' technological infrastructure. Metallo's body eventually downgraded to a more human size and he was also able to shape-shift his body into nearly any mechanical form imaginable. Corben then had a single and uncompromising goal, then the death of Superman.
Metallo not only fought Superman, but he also battled Batman when the Dark Knight found out that Corben killed his parents (Thomas and Martha Wayne) in Gotham City. This later turned out to be a plot by Lex Luthor to get Batman and Superman to fight each other.
John Corben Post-52
Following the creation of New Earth, the John Corben Metallo's history was re-written. In this new origin, he was a solider in service to the US military under General Sam Lane, who had repeatedly tried to hook him up with his daughter. According to Lane's daughter Lois, Corben is a merciless killer. However, Sam Lane treats him like "the son he never had".
After Corben comes to Metropolis to visit Lois alongside Lane and is rebuked by her, Corben volunteers for a protoype of a large power lifter type exoskeleton developed by Lex Luthor for the US Military. The exoskeleton is coated in a special alloy developed by Emmet Vale, called Metallo. The suit is powered by a chunk of Kryptonite.
When the US Military assaults Superman in the Daily Planet building, Superman's laser vision strikes the armor, sending shards of Kryptonite into Corben's heart. Sam Lane asks Luthor to operate on Corben. Luthor agrees, transplanting a chunk of Kryptonite for his heart, as well as giving him a smaller suit of armor. Superman defeats the fledgling Metallo by welding a lead manhole cover to his chest, protecting him from the Kryptonite Radiation, and flying him into the upper atmosphere, as Corben still has to breathe oxygen to function.
Years later, Lex upgrades Metallo to have Red Kryptonite, Blue Kryptonite and Gold Kryptonite. When General Zod, Non and Ursa attack from the Phantom Zone, Metallo joins Lex and his Superman Revenge Squad to counterattack. He kills six Kryptonians- five are exposed to Gold Kryptonite and fall to their death; one is exposed to Red Kryptonite and mutates into a giant ant creature that Metallo then squashed to death.
Following the creation of New Krypton, Metallo teams up with the similar Reactron. They allow Kandorians to capture them, and kill several of them. The two later disguise themselves as Kryptonian sleeper agents in order to go after Nightwing and Flamebird. Following the final assault on New Krypton by Brainiac. Lex Luthor detonated a kryptonite bomb inside of Reactron, destroying the entire planet and killing all those still inhabbiting it. It was during this time while Superman battled General Zod after defeating Brainiac, Supergirl sought out General Lane and not wanting to face his crimes, committed suicide in front of her. Corben knowing his military pardon would not last, fled quickly before anyone of the Superman family could find him.
Post New Krypton
Metallo recently showed up as a member of a "Supergirl Revenge Squad" controlled by the mysterious telepath, Alex. Metallo has been beaten twice by Supergirl, who has thrown his teammates at him to keep him from using his kryptonite heart on Supergirl.
In the current continuity, John Wayne Corben as a solider in service to the US military under General Sam Lane, who had repeatedly tried to hook him up with his daughter, which eventually succeeded. The two dated for a while, but Lois decided she wouldn't become involved with a military man like her father. Corben continued to work with General Lane and eventually became part of the Metal-Zero project. A project designed to have a man using an experimental suit of armor designed by John Henry Irons against alien attacks. Following the debut of Superman in Metropolis, Corben, General Lane and Lex Luthor were assigned with bringing in Superman over his actions against various criminals and business men in Metropolis. The situation lead to reunion between Lois and John, but she rejected his moves towards her. Following Superman's escape, Corben decided to finally activate Metal-Zero with Luthor and Lane, but unknownenly, Brainiac had compromised the suit and the computer systems of the base. The process fused Corben with the Metal-Zero suit and caused his heart to burst on the inside. He was then sent to stop Superman as Brainiac used his Terminauts to shrink and bottle most of Metropolis, similar to the Krypton City of Kandor. Irons, in his own metal-zero suit attacked Corben and defeated him, but Corben was soon transported to Brainiac's ship and escaped. Under Brainiac's control, Corben continued to fight against Superman until Superman was able to reason with Metallo to fight Brainiac's influence due to his feelings for Lois Lane. In doing so, Corben attacked Brainiac until Superman was able to defeat the villain, in doing so, Corben feel into a coma and was taken back by the army. It was revealed that the armor was keeping him alive thanks to the alien technology, but without a heart he would soon die. General Lane told his scientists to find a way to save him since he helped to save Metropolis. He was later given a kryptonite heart to keep him alive since it was the only capatable energy with his cybernetics.
The 3rd Metallo:
Pre-Crisis, Roger Corben, John Corbens brother, had his brain placed into a robotic body to avenge his brother's death. The brain transferring was done by the evil organization SKULL. Roger wanted to avenger his deceased brother and get revenge on Superman. Initially, he posed as a WGBS employee named Martin Korda, but was discovered quickly. He challenged Superman several times, until he was erased during the Crisis on Infinite Earths.
The Post-Crisis John Corben has since adopted the green suit Roger Corben wore.
(Not Including George Grant)
Being a Kryptonite powered cyborg, Metallo does not need sleep, oxygen, food, or water. The suit possesses immense strength, near invulnerability, and is extremely durable and agile. The Kryptonite "hearts", last forever and can be used as weapons (most effectively against Superman and other Kryptonians). At one point, John Corben was powered by green, blue, gold and red Kryptonite. When John sold his soul to Neron for upgrades, they included turning himself into weaponry, absorbing tech, and tech control.
The Roger Corben version appeared in Whatever Happened to the Man of Tommorow?, sometimes referred to as the last adventure of the Pre-Crisis Superman. In it, Corben, along with an army of Metallos, attack the Daily Planet. Corben plans to kill Lois Lane out of anger of her being an "alien lover." Superman is able to use the Daily Planet's large iron rod the planet is on to make a magnet and trap them all. It is never explained how Metallo managed to convert so many people, but is assumed Mxyzptlk had something to do with it.
In Justice, Metallo is a member of the LEgion of Doom. He, along with Solomon Grundy, Parasite and Bizarro attack Superman. Metallo uses his Kryptonite heart to wound Superman, while Parasite drains him and Bizarro beats him. Captain Marvel arrives at Superman's aid, and defeats Metallo by ripping out his heart and throwing it into Parasite. Lex Luthor places the heart back in Metallo, while berating the villains. Supplementary material in the form of Batman's files indicates this is based on the original John Corben version.
On Earth-30, Metallo is created by Lex Luthor to combat Premier Superman.
Batman Beyond In the future, Metallo is still operational but now as a low life thug. Superman and Terry McGinnis easily defeat him despite his Kryptonite heart.
The DC Animated Universe
John Corben was originally a top-tier mercenary. At one time, he led a team of mercenaries to steal the Lexo-Skel Suit 5000 from LexCorp, a theft staged by Lex Luthor for the benefit of the Regent of Kaznia. When Lois Lane tracked the thieves to their ship in Metropolis Harbor, Corben caught her and prepared to kill her, but Superman intervened. To give himself a fighting chance, Corben mounted the Lexo-Skel himself and engaged Superman in a fight that raged across Metropolis, ending when Superman tore the suit apart.
Although Luthor represented to the Regent's lawyer that he had fulfilled his part of the bargain by letting "the Regent's men" take possession of the suit, Luthor subsequently acted as though Corben had been working for him.
Corben was sent to Stryker's Island Prison, where he refused to give details on his employers. For this reason, his cell featured ample creature comforts and gourmet meals, supplied by an apparently grateful Luthor. A few months after his imprisonment, he was shocked to be told he was suffering from a rare and terminal viral disease found only in South America.
Luthor helped Corben escape, and in exchange for his discretion, offered him a way to avoid death: LexCorp scientists would transfer his mind into an indestructible android body made of metallo, possessing strength equal to Superman's and powered by a Kryptonite heart. Feeling he had nothing to lose, Corben agreed.
At first, he was thrilled with his new abilities, which allowed him to fight Superman nearly to the death. However, when he realized that he could no longer smell, eat or feel, he became disenchanted and abandoned the fight. When the LexCorp scientists confessed that that part of his condition was irreversible, Corben went insane, ripping away part of his artificial skin and adopting the identity "Metallo".
Metallo angrily confronted Luthor, who tried to reassure him that his condition could be fixed, given time. Just then, Superman arrived and revealed that Luthor had deliberately arranged for Corben to be infected with the disease. Metallo turned on Luthor, but Superman intervened, and Luthor's yacht was destroyed, leaving Metallo stranded beneath the sea.
Metallo resurfaced from the ocean on a volcanic island, having suffered amnesia after the explosion. He was found by two children, Sarita and Bobby Felix, who decided he was a "hero" because of his resemblance to their action figures. This idea of him as a hero was reinforced when Corben did indeed perform a heroic act by shielding the two children from dangerous pyroclastics when the volcano unexpectedly burst. However, seeing one of their drawings, he remembered Superman, and his identity came back to him. When Superman appeared on the island, helping with the evacuation from a volcanic eruption, Metallo attacked him and nearly killed him. When the kids protested the action of their hero, however, Metallo was distracted enough to allow Superman to throw his Kryptonite heart into the flowing lava. Metallo desperately went after it, but wound up encased in the cooled lava, unable to move or even see. Instead, he focused his mind on his identity, determined not to lose it again.
Metallo was eventually extricated by Intergang, who repaired and even improved his android body, in exchange for which he assisted in a series of bank robberies. When Superman tried to stop him, he severely weakened him with Kryptonite lasers. John Henry Irons, a former employee of LexCorp, helped Superman to defeat him.
Metallo later enlisted Tina, an intern at The Daily Planet, to kidnap Superman. Fortunately, Jimmy Olsen learned of this and went to the Metropolis Junkyard to rescue him. Metallo and Superman battled again in a demolition machine, resulting in Metallo apparently being crushed by falling debris.
Metallo survived once again, however, and returned to Metropolis to join a group of disgruntled villains along with Livewire, Toyman, Kalibak and Weather Wizard. In their fight with the Justice League, Metallo was beaten by J'onn J'onzz, though they seemingly succeeded in killing Superman. Fortunately, this later turned out not to be the case.
When Grodd founded the Legion of Doom, Metallo joined its ranks. One of his missions was to accompany Silver Banshee to the underground world of Skartaris and assist the dictator Deimos in exchange for a large chunk of Kryptonite. However, a League team composed of Green Lantern, STRIPE, Stargirl, and Supergirl, intervened on behalf of Travis Morgan's resistance. In battle with Stargirl, Metallo lost an arm. He then battled Supergirl, who grabbed a knife and removed Metallo's Kryptonite heart.
Metallo was taken to a cave where he was briefly interrogated by Green Lantern. At first he refused to talk, but Lantern pointed out that without his heart his body would shut down within the next few minutes, even seconds. Metallo was about to talk, but his mind was mysteriously shut down by an unknown source. His motionless body was later taken to the Watchtower, to see if J'onn could probe what was left of his mind for information.
Super Man Batman: Public Enemies
Metallo appears as a body guard for Lex Luthor when he goes to talk to Superman. Super Man tries to attack Luthor but Metallo stops him. After having a back and forth for a good while Metallo buries Super Man and Batman alive but they get out and blow up Metallo. Super Man takes Batman to safety because he is hurt. After Super Man and Batman flee the seen Metallo is shown rebuilding himself. For more see Superman/Batman: Public Enemies
Lois and Clark: The New Adventures of Superman
In the episode called Metallo, John Corben, the former Daily Planet reporter got shot and was later taken by the two scientists. The scientists developed a cyborg body for John so that he can defeat Superman. John's girlfriend, Lucy Lane finds out that John was different and later tricked him into luring the scientists' lair. Superman uses his heat vision to stop Metallo by melting both of his legs. The escaped scientist took the powered kryptonite from Metallo's body and Metallo's system was shut down.
The Brave and Bold
In the episode, Batman: The Brave and the Bold: Battle of the Super-Heroes!, Superman was fighting Metallo, hand to hand and Metallo used the Green Kryptonite making Superman vulnerable. Batman takes the Kryptonite out and places in a sealed box allowing Superman to knock him out.
John Corben appeared as Metallo at the 9th Season of Smallville in three episodes. Savior, Metallo & Upgrade . The character was played by Brian Austin Green.
John Corben was a reporter who lived with his sister Rebecca before she moved to Metropolis. He was sent to cover a mission in Afghanistan and from there he kept in touch with his sister through video messages and reminded her to be careful because she was alone in the city. During this time, a truck carrying prisoners had a mishap and was rescued by the Blur but amid the commotion, a murderer managed to escape and ended up killing Becca. John was shattered by this news and returned from his trip to buy the building in which his sister lived. He blamed the Blur for what happened and since then he has been determined to expose him to the world.
John Corben was brought into the Daily Planet as a replacement for Clark Kent who was on indefinite family leave and went to the site of the recent monorail crash to investigate a story. He snuck inside to find Lois Lane looking for clues on the ninja who attacked her. Lois at first presumed he was a detective and tried to leave but Corben played along and questioned her. When a real cop saw the two, Corben kissed Lois and the cop presumed they were just passing civilians and told them to leave. Lois then smiled and stamped on Corben's foot. Corben later went to his desk opposite Lois' and began squeaking his chair and Lois thought it was Clark but saw Corben and still thought he was a detective but Corben revealed himself as a field reporter to replace Clark. Lois says that Clark will be back but Corben says he is on indefinite leave and shakes Lois' hand before leaving.
One night Corben was covering a story that involved the Blur and after talking with Lois and discussing his plans to expose the Blur for what he really is, he was run over by a truck. His bloodied body was found by Zod and his soldiers, who used him to try an experiment to regain their powers. Using stolen technology from LuthorCorp, they rebuilt Corben's body and transformed him into a cyborg with a kryptonite heart. He was abandoned in the building where the surgery took place and after waking was confused and afraid by what had happened to him. He was transported to the Metropolis General and attended to by Dr. Hamilton who informed him that the implants were what had kept him alive. In a fit of psychosis, John gets up scared, and discovered that he now had super strength, and escapes leaving an orderly in a coma. His adrenaline level started to rise clouding his mind making it think that what happened was a gift to kill the Blur for what he had done to his sister. He attempted to track the Blur using the Daily Planet archives, and there he meets Lois, who gives him her key to the Planet's archives room. Realizing that Corben is the man who ran wild at the hospital earlier in the day before fleeing, Lois goes to a phone booth and speaks to the Blur. However, John realizes that Lois had contact with the Blur and decides to kidnap her to find out what she knew. He takes her to the basement of the building in which he lived and after Lois' refusal to collaborate with him, he sent her flying through a wall. Clark appears at that time and tells John that he regretted what had happened to his sister. Corben refused to accept the apologies, and then Clark set off an electromagnetic pulse grenade and momentarily disabled the cyborg. Corben restarted instantly and prepared to kill Lois. Unable to approach the cyborg because of the radioactivity of the kryptonite, Clark heated a lead plate and slammed it into Corben's chest. Realizing the weakness of the Blur, Corben tried to expose his kryptonite heart by ripping the lead plate from his chest, but in the attempt, the meteorite rock stuck to the plate, leaving Corben without power and shutting him down.
At a later point, Tess Mercer received an update on Corben, who had apparently been "repaired". However, the operations have left him more machine than man, also leaving no vital signs. Later, when Tess visited Winslow Schott, a mad criminal genius who used to work for Lex, she gave him John's kryptonite heart for him to tinker with in an attempt to see if he could help reboot John's systems.
Later, when it was revealed that Kandorians were experimenting on humans, Clark asked a doctor if there was any of the humans that were experimented on and never found. The only one was John Corben. Later, it was revealed that Tess' scientists were able to correct the adrenal flaw in the Kryptonite matrix, thereby returning Corben to sanity. Seeing him as a potential weapon if the Kryptonians ever turned hostile, they implanted a control chip into the back of his neck that would turn him in to a mindless drone. Lois infiltrated the base where experiments were being done on red kryptonite just as they were bringing Corben back online. When she was discovered, the scuffle set of an explosion from the red kryptonite, throwing her through the base and down an elevator shaft, only to be caught by the reactivated Corben. Waking up the next morning not remembering how she got home, Lois later found him in the Talon basement. While understandably skeptical after their last encounter, Corben assured her he was now sane and he had saved her the previous night. He explained to her about Tess' experiments and the control chip but also that his artificial heart was nearly out of energy and unless he replenished it soon with more meteor rock, it would deactivate and effectively kill him. Taking him to one of Chloe's weapon stashes, Corben was able to recharge the Kryptonite matrix with liquid meteor rock. He then encountered Clark (who was under the influence of red kryptonite) but before anything could happen, Zod blew the truck up with his heat vision. He survived and Lois found him nearby unharmed, having been blown from the wreckage.
Deciding it was best to get him somewhere safe, Lois was prepared to take him over to the Badlands and out of Tess' reach to a doctor she trusted. Before they could get on the bus, one of Tess' people slipped the control chip onto the port of his neck, instantly taking over his mind. He then returned to the lab, where Tess and Chloe prepared him to stop the Red K infected Clark, who had taken Zod to the Fortress. Chloe, still not trusting Tess deactivated the monitoring system so Tess wouldn't learn the location of the Fortress. Arriving at the Fortress, he was confronted by Zod and Clark. While he had the advantage due to the Kryptonite Matrix, his lack of free will made it difficult for him to effectively battle the two when they split up. The control chip was knocked loose by debris and his mind restored when Clark used his heat vision to bring down part of the Fortress roof on the cyborg intending to crush him.
Coming back to his senses Corben, went straight for Clark again only to be frozen solid by a combination of his and Zod's super breath. This was short lived when they noticed the Matrix began to beat at a faster rate and Corben proceeded to smash his way out of the ice with ease. Being so close to him, they were helpless against the aura of the kryptonite matrix and Corben proceeded to kick Zod into one of the fortress walls. Turning his attention back to Clark, he pulled out a krytonite shard he had been given by Chloe, saying he didn't blame Clark for attacking him in the past but someone who cared about Clark sent him to help. Grinning madly, Clark said he didn't need saving, as Corben knelt down next to him saying from experience that sometimes people don't know when they need saving before stabbing Clark with the shard, freeing him from the Red K. Now back in the right state of mind, Clark lept backwards carefully, observing the cyborg. Corben picked up the removed control chip so no one could control him again and waved off Clark's suspicion of him by saying Clark could thank him another time. He pulled out the Key to the Fortress and placed it in the console, disappearing in a flash of light. After that, John met Lois on the streets of Metropolis. She gave him a new Kryptonite heart, this one being powered by Red Kryptonite instead of green. Corben said that he was going to go underground and wanted Lois to come with him. Lois told him that there was someone else in her life (Clark) and that he was the one. After saying their goodbyes, Corben left. John, now going under the name 'Metallo', was a part of the Toyman's Marionette Ventures league of villains. During their meeting, each member was assigned a target from the Justice League. Metallo's target was Supergirl.