Void: Assimilation theory.
This'll be brief, but I just wanted to get some opinions on this little theory.
Back when Aurelion Sol's lore was released, giving us a lot to think about, I recall it being mentioned that the void was actually many other places across the universe. Then on, I believe, the mid-season update (can't remember), the Rift Herald was created.
The Rift Herald was said to be a less-pacifist version of a scuttle crab, changed by the void. Another, more believable part, is how Kassadin and Malzahar were corrupted by the void. Yet, I don't think Malzahar was changed as drastically as Kassadin was.
For a moment I thought the void could originate from some original beings that created the void. This brings me to the new 'Dark Star' skin line and celestials.
Since celestials seem to be beings originating from creation, and all of them seem to represent certain aspects of 'reality'. Some, I don't really know the purpose, but others, I do. As we mainly just need to focus on Aurelion Sol, he's obviously creation or life. So could the Dark Star faction(mainly Dark Star Thresh) be representing death or corruption? With the theme of black holes, could they just be assimilation?
From now on, i'll mention the figures depicted as 'Dark Celestials'.The dark celestials could very well be opening portals to their version of the universe: a dark, cold, split reality; possibly lacking normal physics and planets. While the dark celestials seem to be more destructive than the normal void corruption, it's still a possibility: as Runeterra hasn't had a first hand canon encounter with one of these dark celestials (luckily for them).
Then we come to what we really know now: the void's corrupting properties.
Basically, of this theory, I believe the void**'born'** aren't born of the void at all: simply the corrupt denizens of a consumed planet's wildlife or civilization. Malzahar and Icathia could be the first signs of a true storm of events. Voidborn could really be controlled telepathically by these dark celestials to do their bidding and spread corruption. Over time, the void's creatures gained power. Enough power to implant visions and ideas into Runeterra's people. Some were able to be swayed to making the void's slow takeover come quicker. (Ex: Malzahar & Friends) The rather varied intelligence could signify that some of the voidborn were once intelligent, perhaps even sentient, creatures.
So far, all the above is the entirety of my belief. Though, its just my headcanon mainly. Tell me if you guys have any thoughts.