Cletus Kasady and Carnage have been killed several times in the pages of Marvel Comics. In “Web of Venom: Carnage Born” (by Donny Cates, Danilo S. Beyruth, Cris Peter, and VC’s Clayton Cowles), readers are taken to the birth of Cletus, when his mother delivers him while being a patient at the Ravencroft Institute for the Criminally Insane. Cletus dies soon after he is born due to being strangled by his umbilical cord, but he is later reborn, with the story strongly suggesting Knull, the God of Symbiotes, returns him to life knowing his important symbiote future.
Carnage continues to face a cycle of death and being reborn. Most infamously, he is ripped in half in space by one of the most powerful heroes in existence, the Sentry, in “New Avengers” #2 (by Brian Michael Bendis, David Finch, Danny Miki, Mark Morales, Frank D’Armata, Richard Starkings, and Albert Deschesne). However, the symbiote manages to keep Casady alive, using its alien powers to put him in a sort of stasis before he is retrieved from outer space.
Carnage dies and is reborn a handful of times more before making a play for the throne of the King in Black, recently transferred from Knull to Venom after the defeat of the God of Symbiotes in the King in Black event. Eventually, Carnage and Cletus split from each other, sending the symbiote down its darkest path ever.