After Hela's defeat, he had been craving a new queen to replace her.

Oh, how thrilled he was when he found you, a lost soul, stuck in between realms, lost and alone, and with a series case of amnesia.

Oh yes.

You will do just fine.

....

Knull, also known as the King in Black, is a major antagonist in the 2024 hero shooter game Marvel Rivals, serving as the main antagonist of Season 3: The Abyss Awakens. He is a primordial deity and the former wielder of the Necrosword.

After the Timestream Entanglement fused multiple universes together, he attempted to free himself from his prison on Klyntar and consume all of them in darkness. With the aid of Hela, who he converted into his queen of black, Knull manages to free himself from his imprisonment and plots to terrorize the cosmos once more.

....

Before the Celestials or even existence itself, there was simply Knull sitting in endless darkness. After the universe was created, Knull tried to return existence to its original state, causing him to perform numerous atrocities against the universe. At some point, he crafted a weapon called the Necrosword, which he used to decapitate a Celestial. He also created an artificial planet and a race of aliens, both of which were called Klyntar. However, the symbiotes eventually rebelled against their master and imprisoned him beneath their planet.

After the Timestream Entanglement, Knull traveled to the Ancestral Plane and imprisoned Bast in a statue. He then tried to convince T'Challa to join his side by convincing him that he was Bast, but T'Challa saw through the illusion and rejected him.

Sometime after Adam Warlock returned to his cocoon and started drifting through the universe, Knull made plans to capture and kill him, as Adam was the only one powerful enough to stop Knull. Warlock's cocoon made it to the planet, however, Adam was rescued by Venom before Knull could capture him. Knull also sent a symbiote to acquire a dead Celestial from Hel, but the plan failed.

....

Knull appears as an imposing, god-like figure with a pale complexion, long white hair, and a dark, armored suit, wielding All-Black the Necrosword as a weapon. His physical presence is designed to embody dread and malevolence, reflecting his status as the dark, ancient King of the Symbiotes.  

....

Location: Klyntar -- The planet Klyntar is essentially a living prison created by symbiotes who rebelled against their creator, Knull, the symbiote god of darkness. Knull, a dark primeval god, resided in the void before the cosmos was created. After being woken by the Celestials' light, he forged the first symbiote with the All-Black Necrosword inside a decapitated head of a Celestial. He later began developing more symbiotes and deploying them throughout the universe to bond with hosts and spread his darkness. When the symbiotes formed bonds with noble beings, they rebelled against Knull. The rebel symbiotes merged to confine Knull within a cage of their own living bodies, becoming the planet Klyntar meaning "cage".

Year -- unknown

Setting -- in Knull's throne room.