Cletus Kasady had a troubled and tortuous childhood of being beat and molested by his father, hated by his mother who loved her dog more than him, killing his grandmother by pushing her down a flight of stairs, and torturing his mother's dog who afterwards tries to kill him and is apparently beaten to death by his father, who receives no defense from Kasady during his trial. Cletus Kasady went to a camp where he was causing mayhem by putting smoke bombs in the girls cabin. Kasady was hiding but was noticed by Billy Bentine, which later took the blame which caught Kasady completely by surprise. As an orphan, Kasady is sent to the St. Estes Home for Boys, where his antisocial behavior makes him the target of abuse from both the other orphans and the staff. Kasady vindicates himself by murdering the disciplinary administrator and burning down the orphanage. When Kasady goes to school he gets a girl friend who later leaves him when he drops out of school. Kasady later becomes a serial killer, to show everyone that laws are just words, and you can do anything you want up to and including murder if you just have the guts.
He is captured and sent to Ryker's Island prison where he shares a cell with Eddie Brock, who had lost his alien symbiote. Brock's symbiote soon returns and bonds with him again, and unwittingly leaves behind the symbiote's offspring behind. This Venom offspring, later named Carnage, gets into a cut on Kasady, thus bonding with his blood and transforming him into Carnage (also causing his symbiote to turn red). He escapes prison, and begins a series of murders, and at the scene of each crime, writes "Carnage Rules" on the walls with his own blood.
Cletus Kasady was created by David Michelinie and Erik Larsen and first appeared in The Amazing Spider-Man #344. Larsen had a strong influence from DC's Joker in his character design. Kasady first appeared as Carnage in The Amazing Spider-Man #361 again by Michelinie with art by Mark Bagley.
Cletus Kasady is one of Spider-Man's most ruthless villains with absolutely no moral compass and little purpose in life except killing and hurting people. Bonded with the Carnage symbiote, the insane Cletus thrives on watching other's blood run and mostly sets his sights on killing Spider-Man or his "father" the Venom symbiote and its respective hosts.
Major Story Arcs
Cletus and the Carnage symbiote pushed a campaign of violence and mayhem throughout New York City with the assistance of Shriek, Doppelganger, Demogoblin and Carrion. They were contested by Spider-Man and many other heroes.
Web of Carnage
When Ben Reilly was acting as Spider-Man, the Carnage symbiote parted ways with Kasady and temporarily bonded with Spider-Man creating Spider-Carnage.
When Cletus Kasady was diagnosed with stomach cancer, the Carnage symbiote left him and briefly bonded to the Silver Surfer. It took the combined might of Spider-Man, the Avengers and Silver Surfer's conscience to separate Carnage from the Surfer. The symbiote returned to Cletus soon after.
During a mass breakout at the Raft, Cletus - once again bonded with the Carnage symbiote - attempted to murder Foggy Nelson. A fellow inmate the Sentry stopped him from doing so and took him into space, out of earth's atmosphere, and tore him in half. Cletus miraculously survived and now has an artificial pair of legs.
Cletus was rebonded with the Carnage symbiote during the Heroic Age. Now revived and ready for more terror, Carnage was opposed by Spider-Man and Iron Man.
Cletus took over a small town in Denver and with his symbiote remodelled the city in his image. He was eventually beaten and imprisoned. But, that never lasts long for this particular symbiote.
Minimum Carnage Alpha
Carnage reappeared in the one-shot Minimum Carnage Alpha. He was working with the Microns. This team promised Carnage that he would have a whole new world to corrupt, take over, and destroy as long as he helps them out, leading them through the Prometheus Pit and into the Microverse. Whether it is by luck, fate, destiny, or comic book writers, the Agent, Venom (Flash Thompson), and Hero, Scarlet Spider, remained hot on his trail. And stopped Radu from using clones of Carnage to destroy both the Microverse and our own universe along with it (Minimum Carnage).
Minimum Carnage Omega
The last book of the Minimum Carnage series (Omega) started with Kasady having the upper hand. He was the first one back from the Microverse and had time to return to his normal size while Venom, Kaine, and Katy Kiernan remained minimized. But, after Venom uses a sonic device on Carnage, Kasady becomes lobotomized. "The symbiote is still in his bloodstream. He's still the alien's host. But without the human side... regardless of how inhuman Kasady might have been... The symbiote's technically in full control. We have the creature sedated now... But Carnage is more dangerous than ever."
Powers and Abilities
Without the Carnage symbiote, Cletus doesn't possess any superhuman or particularly impressive talents. His only real "talent" is for killing things without hesitation. Due to this, he can be seen as having above average fighting skills but most of his victims are helpless. His power is vastly improved with the Carnage symbiote.
In Other Media
Spider-Man: the Animated Series
Cletus appeared in the episodes "Venom Returns" and "Carnage" voiced by Scott Cleverdon. Cletus first appeared holding a young girl hostage and threatening to kill any police officer who attempted to interfere. Upon being defeated then arrested by Spider-Man, the insane Cletus tormented Eddie Brock in the Asylum the two were incarcerated in. Upon seeing Eddie regain his Symbiote at the hands of Baron Mordo, Cletus claimed that he too "wanted the power" and "deserved" it. After Eddie failed to accumulate enough energy for Dormammu, Mordo delivered a second symbiote to Cletus and the two became Carnage.
Cletus ultimately perishes when he is sucked into a portal to Dormammu's dimension.
Cletus Kasady had a small cameo in the episode "Reinforcement". He is seen at the Ravencroft Institution among a support group when Doctor Octopus escapes.
Marvel Ultimate Alliance 2
Cletus Kasady as Carnage is a playable character in Marvel Ultimate Alliance 2. Cletus has apparently allied with the good guys as he was angered by an imposter who had formed the Insidious Alliance in his name. His default costume is Cletus Kasady as Carnage although the Ultimate version of Carnage is also available as an unlock.