Chaos

Chaos, also known as Khaos or Aer, is the first primordial deity and ruler of the cosmos, also known as a god of fate, like his daughter Nyx and granddaughters Moirai. Besides being a deity, Chaos is also a shapeless void below even the depths of Tartarus, the realm of his son of the same name. Once one enters Chaos, he or she becomes nothing, dissolved by the void. From Chaos emerged the Protogenoi (in some myths, with Aether).

History
Chaos was the first primordial deity. He was sometimes considered genderless, but described as male in The House of Hades. He was believed to be the true foundation of reality, particularly by philosophers such as Heraclitus.

The Ancient Greek writer Ovid described Chaos as "a rude and undeveloped mass, that nothing made except a ponderous weight; and all discordant elements confused, were there congested in a shapeless heap."

In the original Greek myths, Chaos was the beginning, the emptiness from whence everything came. From Chaos came sea, earth, and air.

The House of Hades
While in Tartarus, Percy Jackson and Annabeth Chase confronted Akhlys at the "verge of final death, where Night meets the void below Tartarus." Annabeth reacted with surprise that anything was below Tartarus. Akhlys explained that even Tartarus had to rise from somewhere. She showed the two demigods that below them they would see her mother, the earliest darkness, and her father, Chaos. Later, while confronting Nyx and her children, Percy and Annabeth leapt through the Mansion of Night, risking tumbling into Chaos- the void with no return. They managed to make it past both Chaos and the River Acheron into the heart of Tartarus, the current home of the Doors of Death.

Children

 * Gaea (Earth)
 * Nyx (Night)
 * Tartarus (Abyss)
 * Ouranos (Heavens)
 * Akhlys (Misery, Poison)
 * Erebos (Darkness)

Trivia
In other myths he created a brother Aer a lighter form. The atmosphere and cosmos, Like the roman form of a god yet completely different being. He pushed the myth aside yet some cults still pray to him.
 * Some myths name Chaos as the father of Eros. However, in most myths and the series, he is considered to be the son of Aphrodite and Ares.
 * Some myths name Chaos as being in between Tartarus and Gaea, rather than below Tartarus, as stated by Akhlys.
 * Most myths list Akhlys as a primordial goddess born even before Chaos, rather than his daughter, as stated by the goddess herself.