Dr. Karl Malus was fascinated by the subject of superhuman powers since the first time he read a newspaper account of the superhero team Fantastic Four. Upon graduating with a degree in biology from the University of California at Los Angeles, he applied to various institutions for a grant to study supernormal capacities in depth. Unable to get any funding through legal means, Malus contacted certain wealthy investors active in the Los Angeles underworld. They set him up with a laboratory facility he immodestly called the Institute for Supranormality Research, despite the fact that he comprised its entire staff. The underworld provided him with human test subjects to experiment upon, usually individuals the mob sought to liquidate. Malus hoped eventually to find an individual who already had superhuman powers he could study. In the course of research, Malus came up with a number of special toxins and other chemical-based weaponry which he sold to such Los Angeles criminals as the Enforcer.
Malus' first recorded encounter with a superhuman being occurred when the criminal Fly sought out Malus to bolster his waning powers. Malus sent the Fly to steal some special equipment, but the theft led the Fly into battle with the original Spider-Woman. Malus determined to transfer the Spider-Woman's powers into the Fly. He lured her to his laboratory by stealing the comatose body of the Spider-Woman's then-partner, criminologist Scott McDowell, who had been stricken by one of the Enforcer's toxic bullets. After the Spider-Woman defeated the Fly, Malus offered to resuscitate McDowell in exchange for lenient treatment. While reviving him, Malus injected McDowell with an extract of the Fly's blood, which days later caused McDowell's body temporarily to develop certain of the Fly's superhuman powers.
McDowell donned a costume Malus anonymously sent him and for several days wore it, calling himself the Hornet. Malus wanted McDowell to capture the Spider-Woman for study, but the ploy failed, and McDowell eventually returned to normal. About the same time, Jack Russell, unaware of Malus 's criminal connections, contacted Malus in hope of finding a chemical means to curb his rampages as a werewolf on the three nights of the full moon. Malus instead placed a control-collar device on him which enabled him to force the Werewolf to battle Spider-Woman. When Spider-Woman freed the Werewolf, he attacked Malus, wounding him.
Upon his recovery, Malus served only a short sentence before being paroled. He returned to his laboratory to continue his experiments. The dancer calling himself Daddy Longlegs, who had ingested some of the growth formula invented by Henry Pym, sought Malus' help to cure him of his freakish condition. In treating him, Malus acquired a sample of Pym's serum taken from Daddy Longlegs' blood. When Erik Josten, the original Power Man, came to Malus for a means to renew the superhuman strength that the original Baron Zemo had given him, Malus decided to give Josten the Pym growth compound in addition to his strength-augmenting treatment. Hoping to finally have a superhuman accomplice, Malus gave Josten a new costume and suggested he call himself Goliath. Goliath was too powerful for Malus to control, however, and he abandoned him.
Malus later acquired yet another test subject when an ex-convict named Antonio Rodriguez requested Malus's help to cure his wife of an undiagnosed ailment. Malus agreed if Rodriguez would submit to treatment. Malus transferred genetic material from an armadillo into Rodriguez's body, transforming him into a human armadillo. Malus then dispatched Armadillo to free Goliath from the custody of the West Coast Avengers, hoping to assemble a team of henchmen. Captain America defeated the Armadillo, however, and alerted the authorities to Malus' parole-violating activities.
While serving another short term in prison, Malus was contacted by Power Broker, Inc., a mysterious underworld corporation whose major business is the supplying of superhuman manpower to various clients. Malus agreed to join the company in return for getting out of jail. Power Broker, Inc., supplied Malus and his fellow criminal scientists with all of the test subjects they could manage. One of Power Broker, Inc.'s major sources of clients was professional wrestlers who wished to have their strength augmented so they can qualify for the new Unlimited Class Wrestling Federation.
Malus utilized the process by which he restored Erik Josten's strength to augment the power of the wrestlers. To ensure that the wrestlers kept paying twenty percent of their earnings to Power Broker, Inc., Malus administered a highly addictive synthetic drug to the wrestlers, who were told they would die without the drug to stabilize their power, but in reality they would only experience intense withdrawal symptoms. Only five out of ten persons who underwent the treatment emerge with superhuman strength; the rest became brain-damaged or physically disfigured.
Among those treated who escaped addiction was Sharon Ventura, who became the second Ms. Marvel. Malus' experiments were discovered by Captain America, who exposed them to legal authorities, with the help of Demolition Man and the Night Shift. Malus was arrested and is currently in prison.
More recently, Malus was used by the hero team Avengers to give them information on the crime family Maggia in return for a reduced sentence.
Dr. Malus was recruited by The Wizard to be the newest member of the Frightful Four, however after Carnage's resistance to be controlled, both The Wizard and Klaw subdued Dr. Malus long enough to transfer the symbiote into his more easily controllable brain.
Along with a new "superior" Carnage, the villains attacked the City Hall in order to take over New York, but they found themselves against Spider-Man. During the battle, The Wizard lost control over Carnage, and Malus went rogue. Using a vibranium blade he found in The Wizard's hideout, Carnage stabbed Klaw in revenge. The disruption of Klaw's sonic body caused by the vibrainum made the villain explode, taking the symbiote from him in the process. He was killed by The Wizard who was being controlled by the symbiote.