Comic Nexadded February 18, 2020

Hitting #FirstAppearanceFridayjust in time. Unfortunately I was dealing with car troubles. However, let's do a First Appearance of a character I've been dying to do: Knull God of the Symbiotes. He's so effing \m/ METAL!! \m/
Knulls first appearance in full is Venom #3.I say this as there's a lot of cameos before this which alluded to Knull like Thor: God of Thunder #2& #6and he is also teased in both Venom #1& #2.But the first full appearance and one you want as a speculator is Venom #3.
Knull has been around from the very beginning of time, even floating around the endless void before the universe was manifested. There's a long history of Celestial killing, planet killing and forging badass armour and weapons - Gorr - The God Butcher, All Black, the Necrosword.
Eventually Knull is weakened and ends up crash landing on a planet where he begins to control creatures as Symbiotes with him as the hivemind at the centre. This planet, Klyntar, became the centre of the Symbiote empire and from here he sent out Symbiotes to expand.
One of these Symbiotes ends up on Earth in the age of the Vikings where the 'Grendel' is defeated by Thor. At this point the Symbiotes rebel and actually trap Knull in a slumber inside the planet Klyntar.
Thousands of years later, The pieces of the Grendel are found and reunited and Knull is reawakened. He is able to manifest and project via the Grendel to fight Venom and Miles Morales. Bringing us up to date with Venom #3.
The struggle to unleash Knull and reconnect the Symbiotes to him is the core struggle of the Absolute Carnage storyline in progress at the moment.
In terms of powers and abilities the full extent of his power has yet to be unleashed but he is a God, a Celestial Deity and master of Umbrakinesis, the ability to manifest and project darkness as creatures or weapons. He is able to assume some control over other Symbiotes.