Carnage

Cletus Kasady has a troubled childhood, 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 the brink of death by his father, who receives no defense from Kasady during his trial. 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 gains revenge by murdering the disciplinarian administrator, pushing a girl who refused a date with him in front of a moving bus, and burning down the orphanage.

Kasady becomes a serial killer. He is captured and sent to Ryker's Island prison where he shares a cell with Eddie Brock, who had lost the alien symbiote that transformed him into the supervillain Venom. Brock's symbiote soon returns and bonds with him again, and unwittingly leaves behind the symbiote's offspring; the symbiotes reproduce asexually, once per generation; the children are then of no consequence to the parent, hence Brock's symbiote felt no need to inform Brock of the existence of its offspring. The new symbiote enters Kasady's bloodstream through a cut and bonds with his blood, transforming him into Carnage.[5] He escapes prison,[6] and begins a series of murders, and at the scene of each crime, writes "Carnage Rules" on the walls with his own blood. He is found by Spider-Man, though the hero proves to be no match for Carnage's powers. In desperation, Spider-Man makes a truce with Venom to fight Carnage.[7] Carnage is defeated with sonic weaponry, but the symbiote lives on because it is merged with Kasady's bloodstream.

Carnage goes on to recruit an army of psychopathic supervillains including Shriek, Demogoblin, Carrion, and Doppelganger to overtake New York City. They are driven back by Spider-Man, Venom, and a number of other superheroes.[8]

Aside from Cletus Kasady, the Carnage symbiote bonds with Ben Reilly, creating Spider-Carnage,[9] and later the Silver Surfer.[10]

Venom eventually reabsorbs the Carnage symbiote into his own body "for good." Without the symbiote, Kasady retains the Carnage persona by costuming himself in red paint and continuing his killing sprees, but does so as a normal human, only for Spider-Man to easily defeat him in a fight. Kasady finds a replica of the Carnage symbiote in the Negative Zone.

The Carnage symbiote later spawns a "child" symbiote, named Toxin.[11]

Carnage is one of several supervillains trying to escape from The Raft.[12] Sentry finishes him off, flying Carnage outside the Earth's atmosphere and ripping him apart. According to Iron Man's computer, Kasady may not have been inside the symbiote when the Sentry ripped it apart