Unbeknownst to many fans, the X-Men already had their version of the “King in Black” long before Knull ever appeared on the scene. The King in Black is an elder god and the father of the symbiotes (or Klyntar) within the Marvel Universe who made his initial appearance in a Venom comic.
In Venom #3, written by Donny Cates and Ryan Stegman, Knull, also known as the King in Black, made his first appearance. The next issue detailed his complete backstory. According to Venom, Knull was the only one with control over the never-ending vacuum because he existed before the universe had any light.
Knull responded to the creation of the universe and the influx of light life in his realm, transforming the void of the Klyntar, a sentient race of lifeforms. The creation of his All-Black Necrosword, which he used to slay numerous other Marvel gods and cut off the skull of a Celestial, was Knull’s first usage for his symbiotes. The King in Black eventually produced enough Klyntar to form an army, which he sent out into the cosmos to merge the thoughts and bodies of everyone they had under his control into his limitless nothingness.
The first appearance of Knull, also referred to as the King in Black, was in Venom #3, written by Donny Cates and Ryan Stegman. His entire history to explained in the following issue. Venom said that because Knull existed before the universe had any light, he was the only one who could manage the endless void.
The King in Black, as portrayed by the X-Men, is the Age of Apocalypse’s Abyss.
Abyss is a creature of darkness that can transform into and travel through shadow, much like the King in Black, who is the actual god of the Abyss. Despite not being attach to the Klyntar in any known way, Abyss can stretch, detach, and distort his body, similar to a symbiote. However, rather than their physical characteristics or powers, Abyss and Knull have a similar relationship to the vacuum. Abyss has access to the void and can enter it through a hole in his chest. Readers can see Abyss creeping through the darkness of this destroyed planet, engulfing individuals (even a toddler on one occasion), and lowering them into nothingness through the gateway in his chest throughout this issue.
According to the Venom series, The King in Black is the deity of the Abyss and the king of nothingness, and Abyss is essentially The King in Black. Abyss was around first since he made his Marvel Comics debut in the 1990s, whereas Knull wasn’t establish until 2018. This Horseman of Apocalypse has demonstrated a command of the void that surpasses that of Knull-plus. In light of this, it is apparent that the X-Men had their own “King in Black” before Venom because of his powers and prowess and the fact that he was introduce first.