This story contains spoilers for Marvel’s Jessica Jones season 2.
The MCU has been great at bringing in a lot of characters from the Marvel Comics, even if they’re just in it for a few minutes — like in the most recent season of Marvel’s Jessica Jones. If you’ve watched it then you know of the introduction of the character The Whizzer (Jay Klaitz) as someone else created in the same program as Jessica Jones (Krysten Ritter). Or an even more minor introduction of Maynard Tiboldt (Ben Van Bergen), aka the Ringmaster, as the psychiatrist that tries to hypnotize Jessica. But Marvel dug into their collection of mad scientists that create super-powered characters and found Dr. Karl Malus to introduce to the MCU in the form of actor Callum Keith Rennie.
In the series, Malus is working with Dr. Coslov and Dr. Hansen at IGH and save Jessica and her mother Alisa. He also falls in love with Alisa and when he realizes the damage he has caused to the world, he took his own life. The comic book version of the character would never do that. Dr. Malus first appeared in Spider-Woman #30 (1980) by Michael Fleisher, Steve Leialoha, and Jim Mooney. He was the founder of the Institute for Supernormality Research and eventually became a criminal scientist. At first he worked for the Enforcer studying super powered heroes, and then was approached by the Human Fly to find out why his powers were waning. The Human Fly stole some equipment that Malus needed, which brought Spider-Woman onto the case — and her friend Scotty McDowell was shot by the Enforcer’s poison bullet. To save McDowell, Malus experimented on him, turning him into the villain The Hornet. Secretly, Malus wanted a sample of Spider-Woman’s DNA to research but didn’t get it. Later he would find a away to control Jack Russel, the Werewolf By Night, and have him and the Hornet attack Spider-Woman. But the heroine got the upper hand and freed Russell, who then went after Malus.
We would go on to study the criminal Daddy Longlegs, getting a hold of Pym Particles through him and then using them on Erik Jostone to create a new Goliath. He also turned Antonio Rodriguez into the Armadillo and then went to work for the Power Broker, Curtiss Jackson. He would augment the strength of paying customers, though it was risky. They would then use highly addictive drugs, said to stabilize the power, to control his patients. One of these were Sharon Venture, who would go on to become Ms. Marvel and then She-Thing. He would later run up against Vagabond, Daredevil, Madcap, and Hawkeye, never quite getting what he wanted. He then tried to figure out how to de-augment subjects, which ran him afoul of U.S. Agent and Battlestar. He went on to work for the Corporation, the Maggia, and Norman Osborn.
Things took a very different turn when he was recruited to join the Frightful Four by the Wizard and was then forced to be the new host for the Carnage Symbiote, who ate him. He was able to reassemble himself after he was deposited by they symbiote as waste. He is now a human/symboite hybrid. He went to work from there doing experimentations for Serpent Solutions, turning illegal immigrants into animal hybrids. He was even able to capture Captain America and turn him into a werewolf. Malus was eventually captured with the help of Misty Knight and Cap was returned to normal.
As you can see, the character has a long and varied history in the Marvel Comics universe and now has made his live-action debut… and death… in the MCU.