Some things are best left unknown. Strategically, of course, as time travelers are a pain to deal with.

But what can be said is that The Abyss may arrive immediately after Fate, long after the civilizations have faded away, or not at all.(many non-magical Settings lack the infrastructure to support The Abyss. While The Abyss does have some capacity to introduce the needed infrastructure, the many [System]’s that exist are a more effective means of paving the way)

Otherwise, motivations aside. The Abyss is as natural as night to day, as an antagonist is to protagonist, ‘nothing’ by ‘something’, ‘evil’ by ‘good’, and so on and so forth. Every definition needs a contradiction to form a scale of value to define everything. To my knowledge. However, it is not a requisite that an individual be privy to the detail of the contradictions. All that matters is that it does or did exist.

Unlawfully taken from Royal Road, this story should be reported if seen on Amazon.

Life or the creation of a universe is natural(Hopefully). Contradicting such laterally would be creation of life or universe with intent. By Fate, (local)Divinity or Deity’s, that skip/start the natural long term formation and development of natural life and universe.

Contradicting such would be the natural state of decay of existence on all scales; with the largest scale being the collapse of every star and the possible formation of a black hole that would eventually devour everything. Lateral to natural decay is the intent to seek and destroy all living things and all means that create life.

The Abyss has never been explained…