While Erebos is the main realm of the dead in Greek mythology, Tartarus also contains a number of villains from Greek history. 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, by Ouranos, although Kronos later freed. After a while he put them back and had Kampê guard, but they were freed by Zeus and his siblings so they could fight for his cause. The Titans were condemned to Tartarus after their battle with the Olympians. The Hekatonkheires, after the Titanomachy, became the guards of Tartarus with the Titans imprisoned. Kronos is known for being held there.
During the Classical period, writers and playwrights such as Plato and Aristophanes depicted Tartarus as being the place in which the souls of those individuals that were wicked were sent to in order to face punushment. But in this series, the souls of the wicked, including those who, in myth, were sent to Tartarus (Tantalus and Sisyphus), are condemned to face eternal torment 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 beings 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.
Although it is frequently mentioned within the series, Percy Jackson only visits the entrance of Tartarus once. While the group goes to the Underworld to confront Hades, the cursed shoes given by Luke Castellan drag Grover Underwood 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.
At one point, Percy remembers how Kronos had tricked them into almost falling into Tartarus when they went to the Underworld to meet with Hades. He also mentions how Tartarus is like the gods' recycling bin for their enemies.
In the Labyrinth, there is a bottomless pit that is connected directly to Tartarus. Percy does not dare to explore this deep pit.
After Gwen is killed and returns to life on the Field of Mars, Mars himself appears and reveals that Thanatos is captured. He explains that as a result, people are returning to life and monsters aren't staying in Tartarus as they should.
Nico di Angelo leaves camp soon after to gain information on the Doors of Death, Thanatos' personal gateway in and out of the Underworld. It is discovered that Gaea had forced the gates open to allow monsters to reform instantly and to allow souls to escape to fight the gods. Nico is pulled into Tartarus and captured immediately, as the monsters are even stronger in the pit. However, his journey through Tartarus is not written. All that is said is that Otis and Ephialtes had kidnapped him from Tartarus, and used him as bait for the Heroes in The Mark of Athena.
Later when Thanatos is freed, he is able to slow down the revival of monsters, not allowing them to escape Tartarus as they had been.
After being rescued from the giants Otis and Ephialtes, Nico di Angelo reveals that he discovered the location of the Doors of Death. The Underworld side of the doors is located in Tartarus. Nico adds that Gaea's minions are strongest in Tartarus, and despite being the son of Hades, he was overwhelmed and captured immediately. Being there nearly drove him insane and in order to reset the Doors of Death, someone must physically go into Tartarus and cut the chains on that side as well as the mortal side. However, Nico believes this is an impossible task as even he, a son of Hades, barely survived Tartarus and none of the gods including Thanatos himself will go there. While the Seven could possibly free the mortal side of the Doors of Death, they'd need a team powerful enough to fight a legion of monsters in their home territory to complete their mission on the Tartarus side.
Meanwhile, Arachne tells Annabeth Chase that the power of the Athena Parthenos draws monsters from Tartarus; the floor of her chamber is held together only by fragile tile and spider webs, and beneath it is a pit which leads directly to Tartarus. Shortly after Annabeth defeats Arachne with her wits and a Chinese Handcuff, Arachne falls into a abyss made in the ground, leading directly to Tartarus. As Annabeth has a piece of Arachne's silk attached to both her body and Arachne's, Arachne drags Annabeth into the pit. Percy grabs her by the hand, but does not have the strength to pull her or himself back out. Instructing Nico to lead his crew mates of the Argo II to the earth side of the Doors of Death and refusing to leave Annabeth, Percy lets go, and he and Annabeth tumble into Tartarus.
Percy Jackson and Annabeth Chase fall into Tartarus, a fall they only survive as they fall into the River Cocytus which cushions their fall. They discover Arachne also survived the fall, but she is soon killed by Percy with Riptide when she attacks. The two quickly discover that Tartarus is deadly to them to the point that they start to suffocate in the air and form blisters on their skin. They are able to heal themselves with water from the River Phlegethon and start their journey deeper into Tartarus by following Kelli and some empousi who are headed to the Doors of Death. The two are attacked by the empousi but are saved by the amnesic Titan Bob who comes after hearing Percy say his name. After hearing what they are doing, Bob agrees to guide them to the Doors of Death, though the regenerative powers of Tartarus on monsters slowly restores his memory. The three are able to use a Hermes shrine that had fallen to Tartarus to send a message to Camp Half-Blood and encounter a reforming Hyperion and some arai who curse them with curses from dying monsters. Bob learns the truth about Percy destroying his memory, but ultimately helps them against the monsters. As Percy is cursed beyond his ability to heal, Bob takes them to the friendly Gigantes Damasen who is cursed to fight the Maeonian drakon in a Tartarus swamp everyday for eternity. Damasen cures Percy, but refuses to help any further as he believes there is no way out for him. Bob leads the demigods to Akhlys to get Death Mist to hide from the monsters at the Doors. While they get the Death Mist, Akhlys betrays them and they have to fight her and later Nyx. After making their way through the Mansion of Night, the demigods reunite with Bob who regains his memories after an encounter with Koios but continues helping them. At Tartarus' heart, they find monsters returning to the mortal world through the Doors manned by Hyperion and Krios. By the time they reach the Doors, all the Gigantes have returned to the mortal world and Tartarus himself intervenes to keep Percy and Annabeth from escaping. Unexpectedly, Damasen comes to their rescue, having tamed the Maeonian drakon and he, Bob and Small Bob hold off Tartarus so Percy and Annabeth can escape. Before leaving, Annabeth shatters the chains keeping the Doors in Tartarus and with Hazel Levesque severing the chains on the mortal side, the monsters lose control of the Doors of Death and their easy way out of Tartarus.
- Erebos (by some accounts)
- Nyx (leaves during the night and comes back during the day)
- Children of Nyx
- Hemera (leaves during the day and comes back during the night)
- Arke (messenger of the Titans thrown down after the first Olympian war)
- Chimera (According to his collar in The Lightning Thief)
- Titans (some were known to have been released, others may still be prisoners)
- Gigantes (All that have not already risen)
- Numerous monsters that were slayed by heroes.
- Percy Jackson (formerly)
- Annabeth Chase (formerly)
- Nico di Angelo (formerly)
- Small Bob
- It is said that Tartarus is darker than Erebos, which is ironic given that Erebos is the embodiment of darkness and Tartarus' brother (being himself a Protogenos).
- As revealed in Percy Jackson's Greek Gods, the Titans are imprisoned in a maximum-security zone of Tartarus, surrounded by huge bronze walls, and a lava moat, guarded by the mighty Hekatonkheires (though it used to be guarded by Kampê and her minion demons).
- Typhon is currently imprisoned in Tartarus, but the myth says that Tartarus is Typhon's father by Gaea. This fact ironically means that Tartarus is the jailer of his own son, though probably not by choice.
- Tartarus is once misspelled as "Tatarus" in The Lost Hero.
- Between both series, five entrances to Tartarus have been shown. One in the Underworld (main entrance), one in the Labyrinth (destroyed/sealed off), one at the bottom of the Hudson River made especially for Typhon, one in the catacombs of Rome, and one at Epirus, the House of Hades (via the Doors of Death, which have now been removed)
- Nico di Angelo, Percy Jackson, and Annabeth Chase are the first demigods to survive Tartarus (although Gaea's forces finally captured Nico and sent him to the mortal world). In Nico's case, he was captured and sent back to the mortal world, but the experience nearly drove him insane. Percy and Annabeth had the help of the Titan Bob and Gigantes Damasen. Nico didn't think it was possible for a demigod to survive Tartarus due to his experiences in it when telling the Seven about his experiences there and his half-sister Hazel told them no mortal had entered Tartarus and returned.
- According to Nico, Tartarus is so bad that not even the gods go there. Even Thanatos won't go near it.
- Only the Elder Olympians have travelled to Tartarus once, to free the imprisoned Elder Cyclopes and the Hekatonkheires.
- Along with his father Chaos, Tartarus is the only known figure to be both a place and a Protogenoi, with the possible exception of Gaea.
- According to Hesiod, it takes nine days to reach the bottom of the pit. However, time is very hard to tell in Tartarus - nine days in Tartarus could be 9 seconds in the mortal world, and vice versa. Bob says basically the same thing, that time is hard to tell in Tartarus, though he may have been confused due to his memory problems.
- The five rivers that run through the Underworld, the Lethe, the Styx, the Cocytus, the Phlegethon, and the Acheron, all flow into the heart of Tartarus.
- The heart of Tartarus contains one side of the Doors of Death, though this was only temporary as they were chained there.
- Monsters can be killed in Tartarus, but they just reform again in a different place.
- The map of Tartarus shows a door leading to the mortal world, which is presumably used by monsters after reforming.
- Just by being in Tartarus, demigods have their healing powers repressed leaving them at a much greater risk of injury or death
- It is implied in The House of Hades that Leto had once been in Tartarus, but the exacts of that event are unknown.
|Underworld:||DOA Recording Studios | Doors of Death | Door of Orpheus | Elysium | Erebos | Fields of Asphodel | Fields of Punishment | Hades' Palace | Isles of the Blest | Judgment Pavilion | Persephone's Garden|
|Rivers:||Cocytus | Phlegethon | Styx | Lethe | Acheron|
|Tartarus:||The Mansion of Night | Hermes' Shrine | Chaos|