Unyielding Hierophant

The Unyielding Hierophant was a Covenant command-and-control center and refit-battle station that was capable of supporting a fleet of over 500 capital ships. It was capable of Slipspace jumps and was over 10 kilometers (6.2 miles) in circumference. This type of vessel possesses at least two fusion reactor cores for power.

Appearance
"I'm not sure what that thing is. Don't look like any 'uneven elephant' to me—more like two squids kissing."

- Avery J. Johnson

The Unyielding Hierophant is shaped like an eight, with two tear-drop shaped bulbous sections connected at the center, each 15 kilometers (9.3 miles) long or 30 kilometers (18.6 miles) total. A rotating ring is connected to the central hub, where Covenant cruisers and carriers can dock.

Internally it has large "rooms" that are built with foliage and animals to simulate the Covenant's worlds to make occupants feel more at home, rather than on a huge station. These areas even have temples for their religious sessions. In these large rooms, the Spartans reported to have seen pipe-like tubes that carried passengers from one destination to the other in capsules.

The stations appearence has also been described as "two squids kissing each other".

Destruction
At the time of its destruction it was located in the Tau Ceti system. The system was conquered by Covenant forces in 2530 and was therefore used as a rendezvous point for a Covenant force of approximately 500 warships before they prepared to launch their impending attack on Earth. When the UNSC discovered this, the crew of the Ascendant Justice-Gettysburg decided to initiate a first strike against the Covenant to prolong an inevitable Covenant assault against Earth. A team of SPARTAN-IIs, among them John-117, Grace-093, Fred-104 and Linda-058 commandeered a Covenant dropship, after they had reinforced the armor of the dropship with Titanium-A armor inside and out so the ship could withstand the transition from Slipspace to normal space. The team departed and made the transition from Slipspace to normal space in one piece.

The Spartans infiltrated the station, using the Covenant's own tugs to tow them aboard, finding themselves within a hangar capable of docking hundreds of single-ships. Avoiding the Covenant presence, the Spartans proceeded inward, with a copy of the copied Cortana infiltrating the Station's network to distract and hinder the Covenant's coordination. Managing to cross an open plaza with only the loss of one Spartan, Blue team neutralised the Brute guards of a temple and proceeded to the 512 terrawat reactors, with the copied Cortana setting them to overload, which would destroy the station and the fleet nearby.

The Spartans exfiltrated with captured banshees, now taking heavy fire from the Covenant forces aware of their presence. Destroying one of the plaza's windows, they managed to escape, hijacking a floating Covenant dropship and making their way to the evaciation point for the Ascendant Justice-Gettysberg. The Ascendant Justice, separated from the Gettysberg, drew the Covenant's attention to the station with a holographic ruse, keeping them within the blast radius - the detonation destroyed virtually all of the five-hundred strong fleet, the largest victory ever accomplished by the UNSC.

Trivia

 * Due to his trouble reading small text, Sergeant Johnson incorrectly (or jokingly) refers to this station as the "Uneven Elephant."
 * The assault on the station became the Spartan-II's first encounter with Brutes. John is almost defeated by one and Grace-093 takes several Brute Shot rounds to her mid section, killing her instantly.
 * The five hundred twelve-terawatt energy that is used to power the shield generator of the station is strong enough that can repel the collision of a small moon.
 * The 12 ships that survived the stations explosion are believed to be most of the ships the [Prophet of Regret] brought with him to Earth.