Entropy is a creature, a shape, a thing of matter, but it is a devouring wave of anti-life. Its origin is unknown. Its paths are unknown. It is a devouring thing of Chaos that leaves a wall of non-existence behind it.
Hariswiee viewed the creature and the culture developing in chaos of teasing it and feeding it by Lords of Chaos and their creatures. Horrified and indigent he began working on a way to destroy the creature he named Entropy.
A time in the timeless realm passed and many attempts to destroy the creature failed. A culture developed in trackless chaos attacking the creature and many Lords of Chaos and their creatures went down into death fighting it.
In time Hariswee planned a great work, called Paragon. Its tale is long. But even as the Lord of Chaos tried to destroy Paragon themselves, Entropy was attracted by it and flung itself at it.
Failing to destroy Paragon by its bite, Entropy was stunned. Wicked Lords of Chaos empowered a great Artifact of Creation, a tomb, and forced Entropy into it, ripping a vast swath across Chaos. The swath demented the lords of Chaos making them into the Abyssal Lords, and creating the Abyss.
The tomb, now called the Tomb of the Ancestors of Darkness, became the place of rest for creatures of great power and a place of no memory.