Knull made his first appearance in Thor: God of Thunder #6, where he was unnamed and only seen in the aftermath of a cosmic struggle that led to him being rendered unconscious and his Necrosword finding its way into the hands of Gorr. He was first named in Venom #3, where he revealed himself to be the creator of the symbiotes.
Knull has been around since the dawn of the Marvel Universe. As a matter of fact, he lived when there was nothing. Then the Celestials came and shaped the universe, making 'space' as we call it. Knull wasn't fond of this, as this was apparently his domain, or as he calls it, his kingdom. One would question this, since it was all empty anyways, however, he claims that his kingdom, his abyss, was never empty and dead.
Furthermore, he creates a living sword from his shadow. With this sword, he decapitates a Celestial. The other Celestials quickly banished him to the void. This was, however, not a smart idea because the void is where Knull thrives.
He forges a sword, the first race of the symbiotes. His living blade would be known as the All-Black/Necrosword.
Knull realises that he's all on his own. Knull bonds his living abyss with lesser creatures, therefore he's able to draw strength from them and control them. He's now their God, or rather, he's become their God-Host. He can see through their eyes and control them, even from across galaxies. These creatures would later become the alien race known as symbiotes. Knull would also create a planet to act as a throne-world for his conquests- what made it easier was that the planet itself was created out of his creatures, allowing him to corrupt any being that dared to enter his domain.
Expansion and Downfall
Knull's army of symbiotes travelled far and wide, destroying countless planets and stars in the process. The more they took over, the more Knull found out about the universe- each host corrupted by his new creatures had their mind completely accessible by him, so he was able to learn more and more about how the universe functioned, and how the light had taken over most of the Abyss that he once owned.
During this age of conquest, a time displaced Sliver Surfer found himself in this time period, and was attacked by Knull. His powers weakened, Surfer was unable to fight back against him, and Knull attempted to use a symbiote to control Surfer as well. However, a infant Ego, sensing the pain of Surfer, managed to save him with a blast of heat, which kept the symbiote at bay. Knull attempted to catch Norrin using one of his symbiote-dragons, but he was able to outrun it. Ego later nursed him back to decent health, and they fought again, this time with Ego assisting him- however, Norrin admitted that Knull was far too powerful to be destroyed, and used the very last of his Power Cosmic to send Knull into a sun he himself created, and as a result sent Knull blasting through the cosmos. While this slowed him down however, it did not kill the warlord, and he continued his war against the light and the beings who embraced it.
During a battle with multiple gods, he crashed unto a barren and seemingly lifeless planet, where he was subdued and knocked out. During this, a weak and frail alien known by Gorr, who at that moment had been praying for his death as he was hungry and had been banished by his tribe, noticed the battle and where they had fallen, and managed to gain control over the All-Black itself, and killed one of the gods who had been injured by Knull's attack in the process, vowing revenge on all of the gods for their refusal to save him or his son.
While Knull eventually recovered from this attack, he was never able to recover his blade back again: a event that arguably was a grim sign of things to come.
During the sixth century, one of Knull's creatures made it to the planet known as Earth, and attempted to conquer it. The natives at the time dubbed it the Grendel- a creature of darkness itself. However, this creature had the unfortunate fate of encountering the mighty Thor, and they battled, with Thor hitting the creature with a massive divine lightning bolt. This blast was so violently painful that the impact severed the connection between Knull and most of his symbiotes, leaving them without a master controlling their thoughts and feelings. Having bonded to their hosts and established a emotional connection to them, many of Knull's creatures were consumed by the idea of honor and respect, pushing the hive mind to turn against their god by trapping him within the planet of his own making. Unable to control them anymore, Knull was imprisoned within a living prison of his once loyal creatures- trapping him deep within their planet, now dubbed Klyntar, which was their word for "prison" consistently shifting around to ensure that Knull would never be able to break out again.
Ashamed by their actions while under the heel of their creator, Knull was removed from the minds of many symbiotes and they in turn established a new order for themselves, in which they'd be able to govern without a master controlling them. Knull vowed revenge on his traitorous children for what he considered their betrayal.
The Sliver Surfer would almost be trapped by the planet when he stopped by during his days as the herald of Galactus, as the symbiotes attempted to trap him with Knull, perhaps confusing him for their master. He was able to escape and flee after a short struggle.
However, Knull's Grendel creature, while damaged by Thor, was not completely destroyed, and the remains of it would be later discovered by S.H.I.E.L.D., using the parts left over as a Weapon Plus project where they forcefully bonded the biomass of it to injured soldiers during the Vietnam War in a attempt to create super soldiers. While somewhat successful at first, the nature of the symbiotes meant that those bonded to them would eventually turn feral and be uncontrollable, making the project a overall failure: the existence of the project would be almost completely scrubbed from history, with only the Grendel existing as evidence that it ever happened at all.
Through this and other symbiote projects using the Grendel dragon, Knull would eventually gain enough control to project himself through the remains of the Grendel, using it to absorb parts of his biomass back, as well as attempt to reabsorb the Venom symbiote, which at the time was bonded to Eddie Brock. While successful at reintegrating a majority of his form, Knull was unsuccessful in controlling Venom, and retreated. Eddie would eventually destroy Knull's avatar with the assistance of the bonded remains of the Grendel, sonic grenades, and the usage of a blast furnace.
Months later, a attempt by Carnage to establish connection with Knull by killing and then absorbing the genetic codex's of symbiotes in order to connect to the hive mind: the result of this was Knull being able to control multiple creatures both on Earth and on Klyntar, and would reach a pinnacle when Eddie using the Venom symbiote would ultimately kill Carnage, which caused Knull to finally regain connection over all symbiotes on Klyntar, instantly destroying his prison and recreating his dragon army, eager to continue his desire for conquest.
The Wraith, a being that as a child was taken over by the Exolon: parasites that give the user extraordinary powers in exchange for their soul: was attempting to encounter and destroy Knull for many years, due to the mythology behind the Exolon naming Knull himself as their creator. As Knull was contained and trapped within Klyntar (a fact that Wraith himself did not know) he was unable to do this. However, with Knull's presence known by his rampages and current destruction, Wraith tracked him down and demanded answers about the Exolon. Knull, amused by Wraith's headstrong nature, stated that he didn't even remember what they even were. After having his memory jogged, Knull explained that the Exolon were mere failures at creating symbiotic life, and he had discarded them eons ago.
Angered by Knull's words, Wraith would attempt to attack, but was easily stripped of his Exolon by Knull, and sent flying into space. Knull would use the Exolon to create a new Necrosword while Wraith, badly damaged, would die on Earth, having been ultimately disintegrated by using his faulty teleporter.