[1] Klaus Voorhees was a laboratory assistant, working with a professor trying to find a cure for various venomous snake bites.
The Cobra and Mister Hyde formed a criminal team for years, fighting various heroes such as Thor and Daredevil.
His nephew, Piet Voorhees, became the second Cobra and first appeared in White Tiger #1 (Jan. 2007) in a story written by Tamora Pierce and drawn by Timothy Liebe.
Marvel has also used the moniker "Cobra" for two World War II Nazi villains and also a mercenary enemy of Moon Knight.
The Klaus Voorhees version of the Cobra was most commonly associated with Thor, Daredevil and, to a lesser extent, Captain America and Spider-Man.
Klaus was an ex-convict and the Dutch laboratory assistant to Professor Schecktor, a scientist working in India and looking for a cure for venomous snake bites.
[10] He subsequently joined the second Serpent Squad and battled Steve Rogers in his Nomad identity, then he became involved in an attempt to raise the continent of Lemuria up from the ocean.
[25] King Cobra was enlisted by Lucia von Bardas, the former prime minister of Latveria, and placed in her secret army of technology-based villains.
She sent the army against Wolverine, Spider-Man, Luke Cage, Daredevil, and Captain America, the five heroes Nick Fury had sent to Latveria to stop Lucia's secret criminal funding.
After passing of the Superhuman Registration Act in the Civil War storyline, King Cobra was forced to join the Thunderbolts and be trained by the Swordsman, along with Ox and Unicorn.
[26] In spite of this, King Cobra, Mister Hyde, Firebrand and Mauler attacked Yellowjacket, the Constrictor and other Initiative staff and trainees.
[29] King Cobra was among the male Serpent Society members attended the Criminal Technology Show Expo, where MODOK had disguised himself as Arnim Zola.
Iron Man, who had been working with MODOK and disguised as a HYDRA agent, suggested they hide the supervillains before they regained consciousness.
However, King Cobra learned of this and alerted the rest of the supervillains in attendance to MODOK's and Iron Man's scheme, causing a fight to break out.
After Thor defeats Radioactive Man and Mister Hyde, King Cobra and his fellow villains are teleported away and meet with their employer Dario Agger.
[32] King Cobra, Radioactive Man, Mister Hyde, and Grey Gargoyle were instructed by Dario Agger to stand on a rooftop in Manhattan to draw out Thor.
While being transported in a van that says Daedalus LLC: Private Prison Solutions, King Cobra comments to Mister Hyde that he hasn't seen his Calvin Zabo form in awhile.
[35][36] Cobra later appears as a member of HYDRA, led by Baron Helmut Zemo, who are planning to spread poisonous blood extracted from an Inhuman boy named Lucas.
[38] During the "Opening Salvo" part of the "Secret Empire" storyline, the Cobra was with Serpent Solutions when they are recruited by Baron Helmut Zemo to join the Army of Evil.
[39] In the prelude to "Hunted", Cobra was among the animal-themed characters that were captured by the Taskmaster and the Black Ant on Kraven the Hunter's behalf.
[41] Cobra was among the villains that were killed by Black Ant and a restored Hank Pym and revived to join the Lethal Legion.
[42] Klaus Voorhees gained superhuman powers due to the combined mutagenic effects of the venom of a radioactive cobra and an experimental anti-venom.
King Cobra is double-jointed, can dislocate and snap back into place his shoulders and hips at will, and has a phenomenal mastery of his musculature.
Combined with his superstrength, agility, reflexes and reactions, coordination, balance, and endurance, they make him a formidable wrestler.
"Piet Voorhees possesses certain unusual physical powers derived from his mutagenically altered physiology which, among other things, help him simulate the movement of a snake by using his great degree of independent control over every muscle in his body, enabling him to slither across the ground (at up to 50 miles per hour) without using his arms and legs, simply by muscle contraction.
Unlike his uncle however, Piet also possesses enhanced olfactory senses, which enables him to track his targets by way of their scent.
Albri Leiricgrie is a costumed villain who worked for the Nazis during World War II and was an enemy of the Human Torch and Toro.
The Moon Knight had a hard time fighting off Cobra, until he spotted Charles le Blanc using his remote control and shot a dart at it.
[48] Before the Red Guard attacks Santo Rico, Cobra leaves the team alongside Crossbones, Mister Hyde, and Thunderball.
[49] In the Avengers series dedicated to the American Armed Forces, Cobra appears as the founder of the Serpent Society.