Okay so I actually know a little bit about Knull that yall might be interested in hearing about. Also my b if yall already know all this haha. So this dude existed long before the universe did and lived in perfect, comfortable darkness. But then the Celestials, those big dudes from Eternals, showed up and started creating things like stars, planets, etc. Knull didn't like his new noisy neighbors very much so (iirc) he crafted a sword from that darkness and used it to kill one of the Celestials, my headcanon is that it's Knowhere (the big head in Guardians of The Galaxy). It should also be noted that this sword is the same one that was seen in the opening of Thor: Love and Thunder. Anyway, after this, Knull made himself a forge inside the helmet of the Celestial he killed and started making new weapons from it. Those "weapons" are the first symbiotes, and that memory of being forged has been ingrained in the minds of every symbiote in existence (manifesting as their inherent fear of resonant sounds (most commonly clanging metal) and fire). Eventually the symbiote race evolved a sort of sentience and (from what I can remember) bound themselves onto Knull himself, covering him with their "bodies". As time passed the symbiotes kept piling on Knull until there was so many that wrapped themselves around him it eventually became the symbiote home planet "Klyntar" which I believe translates to "prison" or "cage" in their native language. It's also the native name of the Symbiote race as well, the Klyntar from the planet Klyntar. I typed most of this out from a memory I have of one video by Variant Comics called "Knull: God Of The Symbiotes Revealed". It's been a good bit since I last watched this video so some of what I've said might be incorrect so I'd highly recommend yall watch this video, yall could even make it into a reaction I think.