Most people know that Cletus Kasady is Carnage and the trailer for Let There Be Carnage showed that in all of its glory. He's a psychopathic killer who is only made more dangerous by the symbiote inside of him, making him a threat to anyone near him. It's part of what has made him a fan favorite.

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What's less known is his past, his time before becoming Carnage, and how he adapted to his newfound powers. Given the trailer, it's likely some of his backstory will need to be unraveled by Eddie and Detective Mulligan.

10 Cletus Was Taken Care Of By His Abusive Grandmother

Cletus Kasady Behind Bars

As with most serial killers, Cletus' backstory is awful, forcing a child to see the horrors of the world at far too young an age. His mother was purportedly a paranoid schizophrenic at the Ravencroft Institution, who died shortly after giving birth to him.

That led him to come into the care of his grandmother, a woman who was anything but kind to him. She was abusive, treating Cletus as a burden that she wanted nothing to do with.

9 Cletus Killed His Grandmother

cletus kasady kills his grandmother

After all of the abuse from his grandmother, Cletus was bound to hit a breaking point. That day came when Cletus was in the ripe old age of six. He shattered her figurines along the stairs, drawing her into his trap, getting her to gape at their broken forms long enough for Cletus to come behind her.

He shoved with all his might, seeing her tumble down the stairs to her death, all while wondering if she could fly like Mary Poppins.

8 Cletus Tortured His Foster Parent's Dog, Fifi

Cletus Kasady Dog

His actions against his grandmother could be passed off as emotional, striking back against someone he'd always hated. His first true sign of psychopathy was when he tortured his foster parent's dog, Fifi.

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Louise, the foster mother, caught Cletus, and was distraught by what she saw. Fifi was a dog she cared for as if it were a child.

7 He Witnessed His Father Killing His Mother

Roscoe Kasady marvel

The story behind how Roscoe, his father, killed Louise is murky at best. There are two separate stories of the incident. The first is that Louise was so distraught over her dog dying that she tried to kill Cletus. Roscoe stepped in to stop her, accidentally killing her in the process.

If this one is true, it makes Cletus not standing up for his father in court rather heartless. The second story is that Louise was the one who stepped in, stopping Roscoe from beating on Cletus. No matter the story, he still witnessed yet another death, deadening his emotions in the process.

6 Cletus Was Bullied At The Orphanage

Cletus Kasady in jail before bonding with the Carnage symbiote

After losing both his foster parents, Cletus was transferred to St. Estes Home For Boys orphanage. Cletus began to shut himself off from everyone around him while there, displaying more and more anti-social behavior.

None of this was helped by the fact the other kids relentlessly teased him. It caused more and more hate to fester inside of Cletus, a hatred that would soon make itself known to not only the orphanage but to the world.

5 Cletus Burned St. Estes Home For Boys To The Ground

St estes home for boys marvel

Cletus made the kids pay for making fun of him, right along with the staff that let it happen. He killed the disciplinary staff of the orphanage, pushed a girl in front of a bus, and eventually burned the entire place down to the ground.

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It was at this moment that Cletus truly became the homicidal maniac that most know him as. He no longer cared about life and gave into the darkness.

4 Cletus Was Sentenced To Over Eleven Life Sentences When He Was Finally Caught

Cletus Kasady evil smile

By the time the police apprehended Cletus, he'd already killed dozens of people, earning him eleven consecutive life sentences and no hope of ever escaping.

He showed no remorse for his actions, bragging about the people he'd killed and ascribing to a nihilistic philosophy that everyone can commit murder, if they only have the courage to do it. It shows how whacked his mind had become from all of the years of abuse, no longer caring about anything.

3 Eddie Brock & Cletus Met While In Prison

eddie brock and cletus kasady in prison

After losing his symbiote in a battle with Spider-Man, Styx, and Stone, Eddie was sentenced to time in prison. While there, he just so happened to be roomed with Cletus Kasady. The two got along as well as they do when their symbiote takes over.

Eddie detested Cletus' logic behind his killing, seeing himself as the better of the two. Cletus, meanwhile, found it laughable that Eddie thought his symbiote was going to come to save him.

2 Venom's Rescue Of Eddie Led To The Creation Of Cletus

Cletus Kasady transforming

Eddie was proven right when Venom did indeed come to rescue him and at just the right time too. Cletus had grown fed up with Eddie's mouth, preparing to shank him with a homemade shiv before the symbiote's arrival.

Unfortunately, Venom was pregnant at the time, leaving behind a seed in the prison cell. That seed would latch onto Cletus, growing to become Carnage. It's part of why Venom hates him so much, knowing that he was his creation.

1 The First Two Kills He Had As Carnage Were A Prison Guard & Someone He Randomly Picked Out In A Phone Book

Cletus Kasaday Carnage

When Carnage was created, Cletus' first move was to go on a murder spree across the city. He knew no one was going to be able to stand in his way, now that he could kill anyone he wanted.

The first of those people was a prison guard named Ramone, who he dragged through the bars of his cell. The second showed how psychotic Cletus was as he randomly selected someone out of a phonebook. Gunther Stein was the unfortunate soul who was suffocated by Cletus's new powers.

NEXT: Marvel: 5 Best Carnage Storylines (& 5 Worst)