Tartarus (place)

Tartarus (τάρταρος in Ancient Greek) in mythology, is the darkest and deepest area of Hades' realm, known as the Underworld, where the Gods imprison their enemies, who are mainly the Titans, but not just the Titans. Tartarus is also the primordial god of Nothingness, the third one to manifest in yawning void of Chaos. When a monster is slain, it is sent to Tartarus until they reform, for a time ranging from days to centuries. Enemies of the gods that are immortal are sent here as mortal enemies are in the Fields of Punishment.

History
While Erebus is the main realm of the dead in ancient Greek mythology, Tartarus also contains a number of characters. In early stories, it is primarily the prison for defeated enemies. The first beings to be jailed there, however, were the Cyclopes and the Hekatonkheires. The Titans were condemned to Tartarus after their battle with the Olympians. The Hekatonkheires, after the Titanomachy (First Titan War), became the guards of Tartarus with the Titans imprisoned there. Kronos is known for being held there. Later Greek Mythologies depicted Tartarus where the dead souls who were wicked in their lives were also placed. But in this series, the souls of the wicked, including those listed in Tartarus in the myths like Tantalus and Sisyphus are sent to and imprisoned within the Fields of Punishment.

According to the Greek poet Hesiod, a bronze anvil falling from heaven would take nine days and nights to reach earth, and an object would take the same amount of time to fall from earth into Tartarus. Tartarus is described as a dark, gloomy pit, surrounded by a wall of bronze, and beyond that a three-fold layer of night. It is one of the primordial objects that sprung from Chaos, along with Gaea. Though some believe it was a son of Aether and Chaos, whilst Orphic sources claim Tartarus to be the unbounded first-existing entity. Tartarus is also the father of Typhon, of whom Gaea is the mother.

The Lightning Thief
Although it is frequently mentioned within the series, Percy only visits the entrance of Tartarus once. While the group goes to the Underworld to confront Hades, the cursed shoes given by Luke drag Grover to the entrance. When Percy gets to the entrance, Kronos speaks to him, and he realizes that the dreams he had been having before were from Tartarus.

Battle of the Labyrinth
In the Labyrinth, there is a bottomless pit that is connected directly to Tartarus.

The Last Olympian
As Typhon steps into the Hudson River, Poseidon's cyclopes spring from the water and bind him in chains. Zeus strikes him with a lightning bolt and sends Typhon down to Tartarus.

Known Prisoners

 * Ouranos
 * Kronos (Formerly)
 * Erebus (by some accounts)
 * Nyx (leaves during the night and comes back during the day.)
 * Hemera (leaves during the day and comes back during the night.)
 * Arke (messenger of the titans thrown down after the first Olympian war)
 * Typhon
 * Chimera (According to his collar in The Lightning Thief)
 * Titans (some were known to have been released, others may still be prisoners)
 * The Gigantes (some accounts but now are being rising)
 * Numerous monsters that were slayed by the heroes.

Trivia

 * It's said that Tartarus is Darker than Erebus, ironic given that Erebus is the emboidment of darkness and Tartarus' brother (being himself a Protogenos).
 * Typhon is currently imprisoned in Tartarus, but myth said that Tartarus is Typhon's father by Gaea. This fact ironically means that Tartarus is the Jailer of his own son.