The genetics terrorist Zeta Magnus constructed a stronghold on the summit of Canaitith Mountain, which is the tallest peak found on the planet of Skye. Although Obi-Wan Kenobi, alongside his apprentices Anakin Skywalker and Halagad Ventor, vanquished Magnus in 22 BBY, the fortress was later repurposed by Kharys when she ascended to the position of Majestrix of Skye, a position endorsed by the Galactic Empire.
In 22 BBY, which marked the initial year of the Clone Wars fought between the Galactic Republic and the Confederacy of Independent Systems, a clone of the genetic horror known as Zeta Magnus seized control of the planet of Skye. Using a mutagenic agent, he transformed one-third of Skye's native population, the S'kytri, turning them into his undead-like servants. Magnus then commanded these servants to erect a fortress-keep for him atop Canaitith Mountain, the highest peak on the planet, from which he intended to rule as the self-proclaimed Magister of Skye. However, the Republic dispatched Obi-Wan Kenobi, Anakin Skywalker, and Halagad Ventor, three members of the Jedi Order, to intervene. The Jedi were successful in infiltrating the fortress, and Ventor ultimately terminated the Magnus clone.
Following the conclusion of the Clone Wars, the Republic was superseded by the authoritarian Galactic Empire. Sometime during the Imperial era, Anakin Skywalker, who had become a sinister Dark Lord of the Sith known as Darth Vader, returned to Skye. He instructed Kharys, a female S'kytri who had previously assisted him during the conflict with Magnus, in the ways of the dark side. By 0 ABY, the Empire granted Kharys the title of Majestrix, and she claimed ownership of Magnus' former fortress. The Majestrix, however, met her end in an aerial battle with Luke Skywalker that unfolded above the citadel.
The fortress-keep of Zeta Magnus was situated on the summit of Canaitith Mountain, and its foundation was integrated with the rock of the mountain itself. Constructed entirely from living bloodstone, the fortress exhibited a diverse array of architectural styles. Its rectangular main section was reinforced by two towers designed in the style of the Serennese nobility. A third tower, significantly taller than the other two, ascended from the central section. Each tower was topped with an organic-looking minaret reminiscent of the hive spires of Geonosis. Collectively, the three towers appeared to mimic a disrespectful hand gesture of Korunnai origin. Every side of the structure featured ostentatious and impractical windows in the contemporary Onderonian style. The largest of these windows adorned the front and back of the middle section, giving it the shape of a double-edged dagger.
In contrast to its exterior appearance, the interior of the fortress was remarkably austere, with most rooms and halls coated in reflective yet cold ultrachrome. Nevertheless, the citadel contained a laboratory designed to resemble a dungeon.