Oblivion (also called The Void of Oblivion, the Planes of Oblivion, and Wastes of Oblivion), is a collective term used to describe one subset of the planes of existence. The planes of Oblivion are those that have the least connection with the mortal plane, Nirn.
The planes that make up Oblivion are defined primarily by exclusion. Any plane which is not Nirn itself, not one of the planets or moons, and not Aetherius itself, is generally considered to be an Oblivion plane. It is commonly believed that there are an infinite number of such planes, though Tamrielic scholars are aware of only a small handful. In particular, it is believed that each of the sixteen Daedric Princes rules over his own plane, which is formed into an image of his choosing.
Rulers and inhabitants
The rest of the divine planes, which exist outside of the eight planets but still within Aetherius itself, are the planes of Oblivion. These planes have no real connection to the mortal world, and the normal rules of physics do not apply. Scholars assume that only a very few out of a nearly infinite number of such planes are known to mortals, and those that are known share only a few common features. Almost all known planes of Oblivion are ruled over by one of the Daedric Lords, and the plane takes a form reflective of its lord’s personality. The native inhabitants of these planes are collectively referred to as Daedra, and are not mortal in the traditional sense. If they are killed, especially on the mortal plane, their innate spark of life, what is sometimes called their "soul ", returns to a new physical body. However, there is a portion of the universe, the true Void, which is outside of any of the planes of existence; when a sufficiently powerful being manages to kill a Daedra in their native plane, their "soul " is lost to the void forever…
Interactions with Nirn
Unlike the planes of the Aedra, mortals cannot see or detect the existence of the Oblivion planes. Instead, the mortal brain interprets Oblivion as the vast black nothingness of space, literally seeing it as an empty void. The only real indication that Oblivion exists are the sun and stars. These are actually holes of various sizes that were punched through Oblivion at the forming of Nirn, by those Aedra which managed to escape before their divinity was compromised. These holes reach all the way from Nirn , through Oblivion, to Aetherius, and permit the magic of that outer realm to reach Nirn.
Generally speaking, each plane of Oblivion is a unique, distinct world, with its own natural laws and native inhabitants. They range from the violent and inhospitable Deadlands, to the paradise-like Moonshadow. Not all of these planes take a form that even permits the existence of mortals, though most of those known to Tamriel’s scholars have been visited at least once. In addition to those known to be ruled by a Daedric Prince, the powerful college of Imperial Battlemages has made contact with a number of other realms, and built their training grounds (the Battlespire) in several of these.
Planes of the Daedra Lords
Several planes are described in The Doors of Oblivion. These are:
Moonshadow is described as an impossibly beautiful, amazing world made up of impossible shades of colors, and perpetual twilight. This realm is believed to be permanently sealed off from mortals, but those who ventured there in the past usually went half-blind or half-mad from the unnatural beauty.
Boethiah’s Snake Mount or Attribution’s Share
Boethiah’s plane is made up of vast mazes, gardens and labyrinths, and the architecture has a very twisted and sinister appearance. Betrayal and deception are a matter of natural law in this realm. His recent bloody tournament in Oblivion may have been in Mehrunes Dagon’s Deadlands, as it looked basically the same according to the winner.
Clavicus Vile’s Realm
The true name of this realm is not known, but it is one of the most tranquil and peaceful of the Oblivion realms, resembling a rustic countryside.
Hermaeus Mora’s Apocrypha
This is the central repository for all knowledge in the entire universe, and is said to resemble an infinite library. Its books are all identical, having black covers and no titles, but there is one of every book ever written, and includes knowledge normally forbidden to humans. Mortals who wander here usually die and remain behind as ghosts, still seeking knowledge.
Hircine’s Hunting Grounds
This plane consists of a vast expanse of islands, inhabited by the various daedra, or by vast forests, plains, grasslands and puzzling mazes. Hircine’s plane has a higher than normal population of atronachs. And it is home to were-beasts and creatures much larger than those of Tamriel. The most popular hunted prey are those unlucky mortals who find themselves here accidentally. Mortal souls who have been blessed with Lycanthropy are sent here.
The Ashpit is a barren, barely-habitable wasteland. Of those realms accessible by mortals, this is considered the hardest to reach. According to comments made by the Daedra Prince Sheogorath, this plane has some sort of spine in it, due to his comment that the backbone of Malacath’s realm is an actual backbone.
Mehrunes Dagon’s Deadlands
The Deadlands represent as close to the mortal vision of Hell as any of the Oblivion planes. It is also possibly the best known of all Daedric realms to mortals on Nirn. During the failed invasion of Nirn by Dagon’s forces near the end of the Third Era, various Tamrielic forces, especially in Cyrodiil and Black Marsh, actually stormed the Deadlands and won victories there. Ash storms and vast seas of lava make up the majority of this realm, which is populated by the highly intelligent Dremora, as well as many semi- or non-intelligent beings. The beings include Storm Atronachs, Fire Atronachs, Clannfear, Scamps, Daedroth, Xivilai and Spider Daedra. It is from this realm that Dagon has attempted to launch his repeated invasions of Nirn. Jagged rocky formations divide the landscape into miniature valleys. People who fall into the cracks in these jagged rocks oftentimes can never escape.
Meridia’s Colored Rooms
Little is known about this realm, save that the Auroran are native to this plane. This is where Umaril’s spirit fled when Pelinal Whitestrake slew him.
Molag Bal’s Coldharbour
Molag Bal built his realm to resemble an apocalyptic Nirn , where familiar landmarks appear scorched and ruined. It has been described as what Nirn would look like, were it to undergo centuries of cataclysmic war. Mortals who make their way here usually end up in the slave pens or charnel houses.
Namira’s Scuttling Void
Little is known of Namira’s realm beyond its name, and that no known mortals have traveled there and returned.
Evergloam is the mysterious realm of Nocturnal, and seems to have some connection with the “luck” that thieves seem to enjoy. Little is known about Evergloam much like its Mistress . The only known location within the Evergloam is the Shade Perilous , Nocturnal’s fortress within her realm.
Shade Perilous is a location in the game Daggerfall.
This plane is considered to be one of the lowest orders of Oblivion, and is possibly more than one plane. The least of the lesser daedra make their homes here. Little is known of this plane, as it is completely inaccessible to mortals. The closest people have gotten to the Pits were a small band of his worshipers whose spirits were pulled into Oblivion in a botched attempt to summon him. However, it is likely that these spirits ended up in Mehrunes Dagon’s Deadlands, as the plane of Oblivion they were trapped on contained the same superheated red oceans, the same Daedric creatures, and the same dangerous, jagged black rocks. Opposing this hypothesis is the fact that the gate Peryite used to transport a hero to this plane was different in appearance compared to the large, fiery red cat-eye shaped permanent portals of Mehrunes Dagon. This may simply be because a different Daedra opened the gate, or because it was a short term gate.This gate was blue, rectangular. smallish and bordered with broken lengths of levitating stone or some other substance.
Sanguine is said to be in control of tens of thousands of individual, unnamed realms housing all forms of pleasure and decadence.
Sheogorath’s Madhouse (Shivering Isles)
The Madhouse, like it’s master, has a split personality. One half of this realm appears cheery and lighthearted, but hides a deeper manic undercurrent. The other half is more obviously sinister, representing Sheogorath’s demented side. This is one of the few realms that has permanent mortal inhabitants. Each division is ruled by a duke or duchess. Main cities in the Shivering Isles include New Sheoth, Bliss, the Crucible, and Passwall.
The Quagmire is the source of all nightmare and terror. Mortals on this realm describe scenes of impossible horror, which change every few minutes with a blinding flash of lightning into ever more horrifying visions. Mortals in the midst of a nightmare are frequently brushing against the edges of this realm.
Other planes of Oblivion
Chimera of Desolation
This realm, the last of the Oblivion realms in the Battlespire, was created by Mehrunes Dagon to punish a mortal conjurer.
Mankar Camoran’s Paradise
Mankar Camoran, using instructions left by Mehrunes Dagon , created his own personal plane of Oblivion, which appeared outwardly to be an idyllic garden realm, but hid a number of torture chambers and other forms of punishment in the underground areas. Here Camoran’s followers in life are given immortality in this afterlife…but they live only to be preyed on and tormented by Camoran and his Daedric allies.
This is an unaligned plane of Oblivion, also used as part of the Battlespire. It is inhabited primarily by the undead, including an odd race called the Gem Vampires which control the realm. Additionally, the lords of this realm of Oblivion are also called The Ideal Masters.
Relation to Tamriel
At one point during the Oblivion Crisis, the idea is put forth that Tamriel, Aldmeri for Starry Night, is itself a plane of Oblivion. This idea stems from a combination of intentional deception of the part of the speaker, and a basic misunderstanding of how the Elder Scrolls universe is defined. Nirn is the plane of existence that is tied to Lorkhan, much like the planets are those planes tied to the Nine Divines. Presumably, the other Aedra also have their own home planes, though we know little about them. It is true that Nirn is just another plane of existence, like the Oblivion planes. However, by definition, Oblivion excludes those planes tied to Aedra, which includes Nirn itself.
On the other hand, the related idea that Tamriel was somehow “stolen” from the Daedra Lords, by Lorkhan or its population, makes no sense. Tamriel exists only as a result of Lorkhan’s existence, and the mortal population was created specifically to live there.
For the most part, the planes of Oblivion are remote and distant, metaphysically, relative to Nirn. While it is physically possible for inhabitants of certain realms to travel to Nirn and for mortals to enter certain Oblivion planes, it is extremely difficult. In particular, the princes themselves are generally barred from entering Nirn, though they seem to have no problem crossing between Oblivion realms.
The most common means of crossing the boundary between Oblivion and Nirn is by conjuration magic. This allows a mage on Nirn to summon a daedra from one of the Oblivion planes, and bind it to his will, for some period of time. In some cases, the daedra arrives bodily on Nirn ; in other cases, the daedra’s essence is bound into a item, such as armor or weapon, for use by the conjurer. Rarely, a truly powerful magician can permanently bind a daedra to an enchanted item, but typically, the item vanishes once the daedra’s conjuration ends. Extremely powerful mages can also transport themselves to certain of the Oblivion planes; in addition, the Daedric Princes can, in some situations, bring a mortal to their realm. This works much the same as with summoning daedra to Nirn. If a mortal is transported bodily to an Oblivion plane, they can die just like they would on the mortal plane. If they are drawn into the realm magically, it usually involves their body remaining on Nirn , and their death is no more permanent than the death of a summoned daedra.
In the early centuries of Tamriel’s history, Daedric Princes commonly walked on Nirn. Certain Daedra Lords played pivotal roles in the development of the early races of man and mer. Near the beginning of the First Era , after the Ayleid slave wars were over, the Aedra made a pact with Alessia to prevent this from continuing. Since the Aedra’s planes sit between Oblivion and Nirn, they were able to erect barriers that kept the daedra away from Nirn, unless summoned by someone from the mortal side. After this, only a few very rare locations existed where mortals could travel to Oblivion, and the Daedra Lords were forced to communicate with their followers via their shrines, and never in person.
After the Oblivion Crisis however, the joined blood of Martin Septim and Akatosh strengthened the barriers, so now the dragonfires do not need to be lit to keep the barriers intact. Many believed that this would permanently sever Oblivion from Nirn as a shrine or a mortal summoning is required to commune with the daedra .
During the Fourth Era, 500 years after the Oblivion Crisis , the barriers are apparently weaker. Daedric princes and high end daedra are physically manifesting on Nirn. Some manage this through use of a portal of sorts like Nocturnal and the Ebonmere. Some high-end daedra such as Clavicus Vile’s dog Barbas are able to manifest and live on Nirn and even Sanguine himself manifested under a mortal guise.