Chaos

Chaos, also known as Khaos, is the first primordial deity and ruler of the cosmos. Besides being a deity, Chaos is also an 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."

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)
 * Akhlys (Death Mist, Misery)
 * Erebos (Darkness)
 * Pontus (Sea)

Trivia

 * Some myths name Chaos as the father of Eros. However, in 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.