|“||And foes bear arms to the Doors of Death.||”|
The Doors of Death are the personal gateways used by the death god Thanatos' to enter and exit the Underworld. During most of the events of The Heroes of Olympus, Gaea has control of them, but ownership is returned to Thanatos in The House of Hades.
Much like how people can pass into Olympus using a magic elevator, the Doors of Death also appear as an elevator in and out of the Underworld. However unlike the elevator to Olympus, the Doors of Death are framed in Stygian Iron, with black and silver doors etched with art deco designs, making them a complete inversion of the Olympian doors.
The Doors of Death act as a fast passage in and out of the Underworld for Thanatos, who is in control of bringing people to the Underworld, as well as making sure that no one ever escapes as well. Also, Thanatos is able to tell where the Doors of Death are at all times, even if they are not under his control. According to Bob, when the Doors are not chained, they move around after use which keeps them from being found and under Thanatos' control.
When the Doors of Death were in the possession of Gaea, she forced them open while Thanatos was captured and allowed monsters and evil souls to escape the pits of Tartarus in order to help her in her quest to destroy the Olympians and their children. In order to prevent Thanatos from simply moving them, they were chained in place. Also, in order for someone to pass from Tartarus into the mortal world, someone would have to hold the button for 12 minutes and someone else would have to hit the button on the mortal side, or else anything in the elevator would simply vanish. The Underworld side of the Doors were the chained in the heart of Tartarus while the mortal world side of the Doors were chained in House of Hades. Both locations were heavily guarded and both sides of the Doors needed to be freed in order for the Doors to reset. With the Doors in Tartarus, it was considered impossible to free them as no demigod could survive Tartarus and no god, as not even Thanatos himself would go there. For whatever reason only Jason, Hazel and Nico could see the magic of the Doors as they pumped out monsters in mass.
There is a limit to their great power, if it is exceeded it would leave a permanent tear within the mortal world allowing permanent access between the two worlds.
After Rachel Elizabeth Dare takes on the spirit of the Oracle of Delphi, she begins to recite the next Great Prophecy. The last line of the prophecy says that foes will bear arms at the Doors of Death. No one knows what this means, but Apollo says that the prophecy may not come true during the demigods lifetimes.
While Piper McLean, Leo Valdez, and Jason Grace are traveling on their quest to save Hera, they follow a sewer line into a shopping mall. A sales woman there begins to charmspeak Jason and Leo into fighting each other, but Piper figures out that the woman is Medea; a person who died during the time of the original Jason. Though Medea does not mention Gaea by name, she says that the dead are rising because the Doors of Death are opening to those able to help Gaea in her plans. This is proven true as the three eventually meet King Midas and his son, Lityerses; two people who had been dead for centuries. When the trio reaches Detroit on the way to Chicago, they are attacked by three Cyclopes, Ma Gasket, Sump, and Torque. Leo manages to kill them, but notices they are quickly reforming due to Gaea's control over the Doors of Death.
While Percy Jackson is running from the two Gorgons, he claims he had killed them multiple times, but they keep coming back to life after only a few hours, two at most. He later manages to kill them by drowning them in water that puts them off from coming back for further time, by scattering their essence. Later, during the Roman War Games, Gwendolyn is impaled by a spear right through the chest and dies shortly after. However, a few moments later she comes back to life and explains that she was standing at the entrance to the Underworld, but there was an open door that she exited through, allowing herself to return to the land of the living. Mars then appears on the field and explains that the god Thanatos has been captured and eventually, even humans would start to return to life.
Later, Nico di Angelo explains that while the Underworld has many exits and passages that allow those in the Underworld to escape (like Gwen), the Doors of Death are Thanatos' personal way in and out of the Underworld. However, Nico admits that even he does not understand the doors completely. It is around this time that Nico di Angelo leaves to go back to the Underworld to see if he can find the doors from the other side, but was captured by Gaea.
As Percy, Hazel Levesque, and Frank Zhang continue on their quest to find Thanatos, they learn that Gaea fully controls these doors. Anyone working for her, or any spirits/souls that finds these doors can come back to life at an accelerated rate (sometimes instantly). This makes it hard for demigods as their enemies will not stay dead because Thanatos is unable to stop the souls from escaping as long as he is chained. After Frank manages to set Thanatos free, he stops the spirits that Percy is fighting from returning.
Near the end, when Thanatos explains that he does not have the power to close the doors as he is no match for Gaea, but he can make it so that it takes longer for monsters to reform and possibly prevent souls in the Underworld from returning. He also explains that in order to close these doors, the demigods will have to go on a quest to the original Rome, and one of them must be able to read signs that lead them there.
While visiting an island for supplies in Salt Lake City, Hazel Levesque and Leo Valdez find two souls that had escaped the Underworld using the Doors of Death. The two souls were Echo and Narcissus, but unlike other escapees they were not working for Gaea and Echo even helped Leo and Hazel steal the celestial bronze of Narcissus.
Later, after rescuing Nico di Angelo, the group learns about where the two entrances to the Doors of Death are. One is in the city of Epirus in Greece in an underground temple called the House of Hades, while the other entrance is in the deepest parts of the Underworld, Tartarus. While Nico was searching for the entrance, he thought he could go to Tartarus because he was a son of Hades. However, the power of the pit pulled him in and he was captured by Gaea and her forces. Then when the time was right, Nico was transported through the doors to the world of the living, where Otis and Ephialtes used him as bait to lure the crew of the Argo II to them. Nico also informs them that Gaea's most powerful forces are on both sides of the doorway, so while Thanatos is able to return monsters to Tartarus, he is unable to stop them or close the doors.
After Annabeth Chase managed to defeat Arachne, the spider thrashed around, almost collapsing the room which would send them both to Tartarus. While most of the crew manage to escape after Arachne fell through the floor, a strand of spider thread began to pull Annabeth down toward the pit and Percy Jackson quickly ran over to catch her, resulting in being pulled into the pit himself. While they held onto a ledge, with Arachne trying to pull them with her, saying "I go to Tartarus, and you will come too." Percy called to Nico and told him to meet them at the Doors of Death, meaning that Percy and Annabeth would try and find their way from Tartarus to the Doors of Death. Nico understood, leading to Percy and Annabeth falling into Tartarus together.
Back on the Argo II, Nico explains that in order to close the doors, they must be in control on both sides, in Tartarus and in Epirus. While Leo plans on saving Percy and Annabeth, he knows that someone will have to be left behind to close the doors on the Tartarus side, and wonders how Percy and Annabeth will survive long enough to make it to the doors. He says that if he has to make a grabber arm long enough to grab Percy and Annabeth out of Tartarus, he will.Kelli, who is also trying to reach the doors in order to return to the mortal world and take her revenge for being killed. They eventually ambush Percy and Annabeth, who are saved by Iapetus and he takes them to the Doors of Death himself. In order to hide them from monsters, he shrouds them in Death Mist and takes them to the heart of Tartarus. While at the Doors of Death, Percy and Annabeth see many monsters that they had fought in the mortal world, all waiting for a chance to return. They also see that the Doors of Death are chained down in order to prevent Thanatos from calling them. Percy and Annabeth begin to cut the chains holding the doors, but Tartarus appears in his godly form and attacks them. Iapetus, Small Bob, and Damasen (a friendly Gigantes) fight off Tartarus long enough for Percy and Annabeth to break the chains and enter the elevator. Iapetus holds the button for the needed twelve minutes as they won't reach the mortal world if the button is let go before then.
In the mortal world, Nico di Angelo and Hazel Levesque see the massive energy caused by the Doors of Death constantly bringing souls and monsters back from Tartarus and follow the light to the House of Hades. Once inside, Hazel is forced to fight Clytius and Pasiphaë, the two servants of Gaea defending the doors on the mortal side. The see the elevator button light up and are told that is no one presses the button in the twelve minutes it will take for the elevator to reach the mortal world, all those in the elevator will simply vanish. They are also told that all the defeated Gigantes have already been revived with the help of the doors. Hazel uses her control of the Mist to defeat Pasiphaë and Leo manages to hit the up button on the elevator with a screwdriver, allowing Percy and Annabeth to safely exit the Doors of Death. Then with the help of Hecate, Hazel manages to break the chains on the mortal side and the doors reset, vanishing and returning to Thanatos' control.
- Nico di Angelo, Percy Jackson, and Annabeth Chase are the only mortals who have seen the Doors of Death from inside Tartarus.
- Echo and Narcissus are the only known souls to escape the Underworld using the Doors of Death, but do not work for Gaea.
- Some souls that escape the Underworld using the Doors of Death appear to be more ghostly (like Medea and Otrera), while others seem to be completely indistinguishable from regular mortals (like Echo and Midas). It is unknown what causes this.
|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|