The Abyss is a mysterious realm of Oblivion consisting of a never-ending series of rooms and corridors, both real and unreal at the same time, which together form an endless dungeon. Few have survived exploring the infinite reaches of the Abyss, and none have conquered it.
The Abyss seemingly dates back to the early First Era, when the Ayleids ruled over Cyrodiil. A Sorcerer-King named Celemaril Light-Bringer became a lich and attempted to destroy the world. Instead, he was bound within the Abyss by his brother Valentis using an Elder Scroll after a failed rebellion, and nearly every trace of him was wiped from history. It is said that the Lich and the Abyss are forever linked as a true union of the damned, but that one did not create the other. The ancient Ayleids were known to have created Abyssal Altars dedicated to the Lich.
Circa 4E 180, the Warrior was encouraged to enter and explore the Abyss by a madman named Theodor Gorlash (an anagram of "Lord Sheogorath") who was seemingly the Daedric Prince of Madness in disguise. A portal to the Abyss had been opened within an old crypt just outside the Warrior's home town of Rivercrest in the kingdom ruled by the Bloodfall Queen, which was built on the First Era ruins where Celemaril was imprisoned. The opening of the Abyss coincided with the return of Celemaril Light-Bringer after his binding was broken. Familiar with the crypt since childhood, the Warrior entered this portal and embarked upon expeditions deeper and deeper into the Abyss, fighting through waves of enemies and returning to the surface with many treasures, including a number of legendary artifacts. In order to rebind Celemaril within the Abyss, the Warrior reconstructed the Elder Statue in Rivercrest to recreate the original binding ritual. Celemaril susbequently attacked the town with an undead army, but was defeated in single combat by the Warrior and sealed within the Abyss for several more millennia.
The rooms within the Abyss vary in appearance, with each floor of the dungeon containing a different architectural style and increasingly difficult enemies. The rooms can take on the appearance of natural caves, ancient Ayleid ruins, and Imperial forts. These rooms are inhabited by an endless number of various enemy types, including mortals, Daedra, goblins, Tamrielic creatures, undead, and even dragons.
- In the book The Doors of Oblivion, a realm called Marukh's Abyss is mentioned. It is unknown if these two realms are connected, since Marukh's Abyss is untraceable from what little information was left behind.
- Theodor Gorlash's dialogue in Blades
- Abyssal Hourglass item in Blades
- Shulkunaak's dialogue in Blades
- Saashi's dialogue in Blades
- Abyssal Altar item in Blades
- Junius the Elder's dialogue in Blades
- Default Town name in Blades
- Events of Blades
- Wrath of the Sorcerer-King quest in Blades
- The Doors of Oblivion — Seif-ij Hidja