From Halopedia, the Halo wiki
Zhoist, or Light To The Path, is a planet in the Buta system. It was formerly controlled by the Forerunners, but was later settled by the Covenant. In 2526, it became the site of an attack by the United Nations Space Command's Task Force Yama. During their attack on Zhoist, the UNSC forces gave the planet a designation of Naraka.
Topography and ecology
Zhoist's surface, when viewed from orbit, resembles a pearl-coloured marble. The planet's sky has a yellow haze to it, with the surface a rich volcanic world of fuming calderas and glowing rifts. Where the ground isn't steaming or bubbling, the Covenant have constructed walled fields and serpentine terraces. A silvery web of luminous roadways converged on large cities of ivory domes and golden spires, built around the massive gravity lifts serving as the Covenant's space elevator equivalents. On close inspection, the large domes are revealed to be in fact clusters of tall buildings, each hundreds of metres tall and appearing to be centuries old and resembling hand-blown glass. The planet is littered with Forerunner structures, with many of the world's ancient storehouses and facilities having been lost to the planet's active volcanism over the millennia. From space, a massive continent-sized structure resembling the Eld symbol can be seen half-buried under the surface.
Prior to the Great Purification, the Forerunners had a large presence on Zhoist, establishing what would come to be known as the Ten Cities of Edification. Although many of the vast facilities supporting the cities eventually succumbed to the planet's active volcanism, the cities were able to survive for a hundred millennia relatively untouched.
The Covenant would eventually discover and settle Zhoist during their early expeditions, coming to revere the planet as holy due to the Forerunner presence there. The ancient guild halls dominating the hallowed cities were the source of many of the technologies that powered Covenant starships and weapons. Thousands of Covenant artisans and engineers worked on Zhoist to research these artifacts. The Covenant established a series of gravity lifts and orbital space stations around the planet, with a complex web of fleet support stations termed the Ring of Mighty Abundance. The third, fourth, and fifth Lagrange points in the Naraka/ Rudara planetary system maintained picket squadrons in an equilateral triangle for defending the orbital facilities around the planet.
By the time of the outbreak of war with humanity, Zhoist served the Covenant as a vital supply base and staging area for the Fleet of Inexorable Obedience. During the Battle of Chi Ceti in 2525, the Unrelenting intended to return to Zhoist for repairs following victory against the humans, before its destruction at the hands of Blue Team. By 2526, Zhoist maintained a small defensive rapid-response flotilla and its shipyards were in the middle of constructing the Supercarrier Hammer of Faith. Following the successful Battle over Etalan, Task Force Yama targeted the planet for Operation: SILENT STORM, with Doctor Catherine Halsey determining the planet's location due to the planet's status as the only habitable world within jump distance of Transit Point Bhadra. She named the planet and its moon Naraka and Rudara respectively, due to not having discerned the Covenant names and in honour of the late Captain Halima Ascot's Hindu background.
On April 15, 2526, Task Force Yama's Dagger Force and Sierra Force launched a joint attack on Zhoist, with Dagger aiming to take out the lagrange point stations to distract the fleet while Sierra deployed troops onto the planet to destroy Covenant infrastructure supporting the Ring and fleet stationed there. The resulting Attack on Zhoist saw the destruction of two of the Ten Cities, the Ring of Mighty Abundance and several of the large gravity lift space elevator structures at the hands of UNSC nuclear weapons.