An Unidentified monolith was a structure located centrally within the Chiloon Rift. This structure served as a conduit to a mysterious realm, possibly the world of Mortis.
This monolith functioned as an entryway to a strange world populated by spectral entities. These beings possessed the ability to bestow upon individuals access to the Force, but this gift came at the cost of the recipient's sanity.
During 45 ABY, the Columi siblings, Craitheus and Marvid Qreph, stumbled upon the monolith while orchestrating a financial takeover of the Chiloon Rift. They discerned that a Space–time-warping gate existed, which provided passage to the monolith, and subsequently constructed a base above this gate. However, further investigation revealed that the gate could only be activated through the Force. In order to gain entry, they enlisted the services of Savara Raine, a mercenary. Raine, accompanied by Barduun, a Mandalorian as backup, ventured into the monolith. Upon encountering the shadowy figures, Barduun succumbed to madness, and Raine narrowly escaped. The Qrephs, enthralled by this development and eager to harness the Force, but wary of suffering Barduun's fate, postponed their own entry until they could gain a better understanding of the mechanism.
However, the Qrephs' actions within the Chiloon Rift drew the attention of the Jedi. Ohali Soroc, a Quest Knight who was searching for the similar Mortis monolith, arrived at the Chiloon Rift monolith and encountered the Qrephs. She was captured and tortured at their base while they attempted to determine how to deal with her. As pressure from the Jedi increased, the Qrephs decided to enter the monolith despite the inherent danger. However, Raine, having witnessed Barduun's fate, refused to participate. To bypass Raine's refusal, the Qrephs generated several clones of Force-sensitive individuals, including Ohali Soroc and Savara Raine, to facilitate their access. The Jedi eventually located the monolith and attacked the base situated there. Unable to delay any further, the Qrephs utilized the Raine clone, Savara Two, to enter the monolith. The Qrephs were pursued by the Jedi, Leia Organa Solo and Luke Skywalker. Although the Qrephs successfully acquired Force-sensitivity within the monolith, they were ultimately killed by the Jedi. With the Qrephs defeated, the Jedi escaped the monolith. Three months following the Jedi assault, the monolith was sealed off to prevent any further access to its perilous power.