|Appears in||Oblivion, ESO|
The Dark Fissure contains one of the four mysterious altars in Cyrodiil that are necessary in the creation of a Black Soul Gem, a phenomenon known as the "Shade of the Revenant." The Dark Fissure is found in the smaller region of Mist Morrow Vale.
It is unknown when the altar at the Dark Fissure was established but by the mid-Second Era, an abandoned and undiscovered Ayleid ruin was present where the cave is currently located. An adventurer from Vlastarus traveled to the Dark Fissure amidst the Alliance War in 2E 582, to explore undiscovered Ayleid ruins. But she was later killed by unknown sources. As the Alliance War raged across central Cyrodiil, the Dark Fissure was considered within the Ebonheart Pact's territory of the region.
Many years later in 3E 433, the Dark Fissure was inhabited by a coven of Necromancers and an anchorite of the Worm God, Mannimarco. The anchorite lived in isolation from civilization, conducting the Shade of the Revenant, and producing Black Soul Gems. At the time, the Arch-Mage of the Cheydinhal Mages Guild was revealed to have been involved in necromancy, with knowledge on the altar locations throughout Cyrodiil. Master-Wizard Raminus Polus sent a Conjurer of the guild to investigate the Dark Fissure, where they uncovered the altar. The Conjurer returned to the Arcane University with the knowledge on the creation of Black Soul Gems.
A "Dark Fissure" may also refer to small portals akin to the Dark Anchors of Molag Bal, which are gateways to his plane of Oblivion, Coldharbour. These Dark Fissures can be found in the wilderness, without any setup like the Dark Anchors. They were somewhat prominent during Molag Bal's invasion in 2E 582, the Planemeld.