WARNING: The following contains spoilers for King in Black #1 by Donny Cates, Ryan Stegman, JP Mayer, Frank Martin and VC's Clayton Cowles, on sale now.
When the symbiote god Knull was awakened at the end of Absolute Carnage, he quickly set his sights on Earth. For the past year, the cosmic god has been traveling across the cosmos with his army of symbiote dragons, killing whatever and whoever he came across. As he spread death and destruction, Knull only kept on adding numbers to his ranks as he took over the bodies of the fallen with his symbiotes. And now, he has finally arrived on Earth in all of his dark, regal glory.
In King in Black #1, the army of symbiote dragons begins to swarm Earth's atmosphere, and the Avengers and the rest of the world's heroes begin a coordinated plan to fight back. But even a space landmine field and the best team of superheroes can't hold back Knull's force, especially not when the god of the symbiotes reveals his secret weapon: symbiote-covered Celestials.
Before Knull even touches down on Earth, the first wave of his army invades the planet. The symbiote dragons start by attacking the cities, and they rain down from the sky, covering the ground in symbiotes. However, that's only the start of Knull's attack. Just as the Avengers start to become overwhelmed by an incredibly large number of dragons, the second wave of Knull's army arrives in the form of a horde of symbiote Celestials.
The Celestials are massive, ancient cosmic beings responsible for the birth of the Marvel Universe. They are akin to gods, and they possess great power. And now, Knull has managed to kill them, and he has corrupted them with his symbiotes into even more powerful and frightening entities.
This isn't the first time Knull has tangled with the Celestials. In 2018's Venom #4, Cates and Stegman revealed the god of the symbiote's origin, which dated back to the birth of the universe itself. After the Big Bang, Knull, a creature of the dark abyss, found himself in a place filled with light. In this infant universe, he rapidly found enemies in the Celestials, and he engaged them in combat. He was able to sever a Celestial's head, which would, thousands of years later, become the space station known as Knowhere.
This is why, when Eddie Brock becomes aware of Knull's symbiote Celestials, the anti-hero says "Knull's first enemies were the Celestials... and it looks like he's settled the score." Thanks to his connection to the symbiotes, Eddie knows Knull's history, and he knows that his rivalry with the Celestials dates back a very, very long time.
For the time being, it's unclear if Knull has killed all of the remaining Celestials. In King in Black #1, his army includes three of these corrupted cosmic beings, but it's not clear if Knull has more. Thankfully, the Sentry is able to kill one of them, which means that Knull has just suffered a considerable loss. If the villain is down to two Celestials, then the impossible task in front of Marvel's heroes just got slightly less imposing.
Still, with the Sentry now dead, Thor missing and most of the world's heroes down for the count, these other two Celestials will prove incredibly difficult to destroy. By the look of things, it sure looks like Knull has won. And now, he and his dark Celestials have wrapped their tendrils around the Earth in a dark embrace.