Cletus Kasady or known in the future as Carnage, is a major antagonist in Sony Pictures Universe by Marvel Characters, he serves as a minor antagonist in the story in the 2018 film called Venom and the main antagonist in the sequel to Venom: Let There Be Carnage. He is a serial killers who is arrested in San Quentin Prison, and was intertwined by Eddie Brock.
Kasady was born in Brooklin, New York. When Kasady was a child he developed his psychopathic traits by torturing and killing his mother's dog, he also killed his grandmother by pushing her from the stairs. He also made a girl who rejected him getting hit by a bus. During his adult years, Kasady became serial killers and started killing and torturing people, it may also have been speculated by Brock that Kasady might have Oedipus Complex.
Interview with Brock
Then when Riot and Carlton Drake are killed, Eddie Brock, who now rides his motorcycle, decides to go to San Quentin Prison, to interview a serial killer named Cletus Kasady who tortured and killed many people. Once there, he sees blood on the wall that was made by Kasady, and he still announces to Brock that he will get out of jail and unleash a carnage.