The Deep Ones are a race of beings who dwell deep underground beneath the town of Hackdirt, an isolated Imperial settlement in Cyrodiil's Great Forest. They are worshipped as gods by the inhabitants of Hackdirt, who built the Chapel of the Brethren in their honor. Worshippers who have changed the most are known as the Brethren, and dwell underground in the Hackdirt Caverns to be closer to the Deep Ones. The other residents descend into the caverns at night for "Gatherings" where they worship the Deep Ones; tunnels were dug connecting each house to the caverns for this purpose.
Hackdirt was refounded in the Third Era as a mining town by Irlav Moslin. Digging in the mines, the villagers discovered natural caverns running beneath the town, and supposedly discovered the Deep Ones. Irlav met with the Chief of the Deep Ones, who taught Irlav his language and his runes, passing on the ancient lore of his people. The villagers recorded this lore in the Bible of the Deep Ones and devoted themselves to following these teachings for eternity. This bible was written using Daedric runes, and was an excerpt from the obscure text N'Gasta! Kvata! Kvakis! written by the Sload necromancer N'Gasta.
The Deep Ones helped the inhabitants of Hackdirt, making them rich, but demanding blood sacrifice and worse in return. These activities ultimately resulted in the Imperial Legion being called in, resulting in deaths and the destruction of buildings. The arrival of the soldiers drove off the Deep Ones, who never came back.
People continued to live at Hackdirt and in the caverns below, including Vlanhonder Moslin, the grandson of Irlav. In 3E 433, around thirty years after the Legion's intervention, the villagers planned to bring back the Deep Ones through ritual sacrifice. They captured an Argonian named Dar-Ma, the daughter of a trader from Chorrol, and imprisoned her in the caverns. However, this plan was foiled when the Hero of Kvatch arrived at Hackdirt in search of Dar-Ma, resulting in her rescue and the deaths of many of the Brethren.
The only remaining presence of the Deep Ones is a low growling which can be heard throughout the Hackdirt Caverns.
- Deep Druids, druids that worshipped and communed with the unknowable entities that dwell in the abyss beneath the seas
- Sunken One, a similar entity worshipped by local farmers in the West Weald
- Appearance of Hackdirt in Oblivion
- Jiv Hiriel's dialogue in Oblivion
- Appearance of Hackdirt in ESO
- Bible of the Deep Ones — Irlav Moslin
- N'Gasta! Kvata! Kvakis! — N'Gasta
- Artisa Arelas' dialogue in Morrowind
- Honditar's dialogue in Oblivion
- A Shadow Over Hackdirt quest in Oblivion
- Hackdirt Caverns in Oblivion
- The Annotated Anuad