As the Theos waged war against themselves, effectively making them almost extinct. The second predator of the cosmos hierarchy wreaks havoc on the Nexus tree.
Nulls keep them docile for eons and eons. On one unlucky day, Nulls made a mistake, on that infinitesimal slice of an instant Nulls was thrown into the first reality his kind had ever conquered.
Nulls spent years on that reality, only to get thrown into the second, then the third. Each reality differs radically from the last.
Then, along the way, he realized. The only way to be freed was to stop whatever gnawing at the Nexus tree.
Armed with nothing but his intellect, Nulls embarked on a journey to stop the multiverses from being destroyed.
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Nulls, the last surviving member of Theos, a godly advanced eldritch horror species.
The Theos are impossibly intelligent and possess advanced technology, particularly reality manipulation. They can alter the forms and fabric of the space-time of multiverses, putting them at the apex of creation with no predator.
An emergence of a potential predator was pre-emptively devolved, before the said being could form a thought.
Sometimes they removed the physical constant entirely. They also exhibit cruelty and a desire to dominate and reshape other realities.