The Holocron of Belia Darzu, a Sith holocron, was crafted by Belia Darzu. She was a Dark Lord of the Sith ruling during the final years of the New Sith Wars. This four-faceted, pyramidal device, the holocron, stored Lord Darzu's insights into the dark side, notably Sith alchemy and the Force power called mechu-deru. After Darzu's assassination, the holocron remained within her stronghold on the planet Tython, acting as the last remnant of her influence.
Centuries afterward, during the Golden Age of the Old Republic, Darth Bane, a Sith Lord in search of the means to construct such a device himself, retrieved the holocron.
The holocron, a four-sided pyramid-shaped device, was made by Belia Darzu, the Shi'ido Dark Lord of the Sith who was female. It utilized a crystal matrix capable of holding vast quantities of data, including Darzu's philosophies concerning the Force, her mastery of Sith alchemy, and the dark side technique known as mechu-deru. Furthermore, it contained instructions for building a holocron, detailing the complete procedure—including the complex Rite of Commencement—and displaying sectional views of such a device. Upon activation, the holocron projected an image of Lord Darzu, serving as its gatekeeper and replicating both her appearance and her inherent shape-shift ability.
In 1250 BBY, during the final years of the New Sith Wars, Belia Darzu, a Sith Lord, spearheaded the re-established Sith empire during the Sictis Wars. Before 1230 BBY, Darzu constructed a Sith holocron. Inside this device, Darzu documented her views on the Force and expertise in dark side arts, along with thorough instructions for holocron creation.
The holocron was secured within the subterranean inner sanctum of Darzu's fortress located on the planet Tython, and it remained there after her assassination in 1230 BBY. By then, the holocron had absorbed dark side power, becoming the last tangible trace of its creator. The dark side energy emanating from the device permeated Darzu's fortress, attracting the remaining members of her technobeast army and causing them to cluster around it.
In 990 BBY, Darth Bane, a survivor of the New Sith Wars seeking the knowledge to build his own holocron, discovered Belia Darzu's holocron. After infiltrating Darzu's fortress and defeating a swarm of surviving technobeasts, Bane acquired the holocron and studied its contents while interacting with the device's gatekeeper. The holocron was briefly entrusted to Darovit, a Human male who concealed it during an intense lightsaber battle inside the fortress. As the fight concluded, Darth Zannah, Bane's apprentice, recovered Lord Darzu's holocron before venturing to the planet Ambria.
The holocron of Belia Darzu was initially featured in Darth Bane: Rule of Two, the second book in Drew Karpyshyn's Darth Bane Trilogy, during 2007. It later gained its own entry in The Complete Star Wars Encyclopedia, which was published in 2008.