In the final months of the Human-Covenant War, the Prophet of Truth had a massive fleet under his personal command. Originally composed of over five hundred capital ships, it was initially one of the largest known Covenant fleets. However, the fleet suffered tremendous losses when its command-and-control station, Unyielding Hierophant, was destroyed. After rebuilding the fleet for some time, Truth sent it to Earth, where it was later joined by remnants of the Covenant forces loyal to the Prophets from the High Charity defensive fleet and Truth himself. Later, the fleet journeyed through the Portal to the Ark, where it met its end.
After the Prophet of Truth discovered the location of the human homeworld, he started assembling a fleet of over five hundred warships for the planned invasion of Earth. Ships scattered around the galaxy were ordered to regroup, including one group of ships that was to jump to the Lambda Serpentis system, to gather tritium gas for their reactors and then the Hawking system to meet with three dozen assault carriers and effect a transfer of Seraph fighters. Finally, the fleet would be summoned to the command-and-control station, Unyielding Hierophant which was holding position in Tau Ceti system in September, 2552. When a sufficient amount of ships were gathered, the fleet would then make a collective jump straight to Earth.
Due to Truth's devious plans for the Covenant, this fleet was commanded exclusively by the Jiralhanae and featured only few Sangheili in its ranks; an arrangement unheard of in the Covenant before the Great Schism. For similar reasons, Truth kept the existence of this fleet, and the fact he had discovered humanity's homeworld, secret even from his fellow Hierarchs.
However, Truth's plan was slowed down when a small group of human survivors from Reach and Installation 04 discovered the fleet, leading to the destruction of the Unyielding Hierophant at the hands of a team of SPARTAN-IIs. Only a dozen ships survived the station's explosion.
While Truth was rebuilding his invasion force, the Prophet of Regret, completely oblivious of Truth's plan, discovered the location of the gateway to the Ark by decrypting Forerunner artifacts; coincidentally, this structure was located on Earth. Unaware of the human presence, Regret led a detachment of fifteen ships to Earth. While he learned of this upon arrival, he was so blinded by his religious fervor he ignored Earth's orbital defenses and sped to the planet surface, immediately deploying troops to the African city of Mombasa in search of the Forerunner artifact, while his ships fought the UNSC Home Fleet in orbit.
 Invasion of Earth
Immediately after the Prophet of Truth learned of Regret's departure to Earth, he sent his fleet after him. The Jiralhanae in command were given orders to eliminate the Sangheili still in command of what was left of Regret's fleet and ground forces; an order they would willingly obey. While Truth's fleet was on its way, Regret was forced to retreat as UNSC forces retook the city and approached his ship, making an emergency Slipspace jump in the middle of the city.
Only moments later, Truth's fleet arrived, and as ordered by Truth, the Jiralhanae assumed command of the remainder of Regret's ships, battling UNSC forces within New Mombasa and briefly occupying the city. In addition, they killed any remaining Sangheili troops still stationed on or above the planet. On the same day, as more Covenant warships began to arrive, Truth's fleet started excavating the Forerunner structure by glassing the planet surface around it, including Mombasa, starting from the crater created by the in-atmosphere slipspace jump of Regret's ship. For the next two weeks, more and more Covenant reinforcements sent by Truth would arrive, securing the planet for Truth's arrival nearly a month later. During this period, fleets such as the Fleet of Furious Redemption would join Truth's fleet and the battle raging in Sol System. While maintaining a significant presence in orbit, the fleet deployed ground forces to multiple targets around the globe, including Mount Erebus, the Yucatan Peninsula and Havana, Cuba. The SPARTAN-II Blue Team fought the Covenant forces in multiple operations on and around Earth, halting most of their excavation operations. On November 3, after the Battle of Havana, one of the fleet's ships, the Bloodied Spirit, was captured by the Blue Team and taken to Onyx. Despite the UNSC resistance, the fleet's ships in East Africa managed to continue their task of uncovering the Portal.
After the Flood overwhelmed High Charity and its defensive fleet, the surviving Jiralhanae-held ships managed to follow the Prophet of Truth and his Dreadnought to Earth, where they joined the fleet that had arrived earlier. For a period of nine days, the Dreadnought traveled through the system, eventually entering Earth's atmosphere on November 17th. Before the Dreadnought reached Earth, the Fleet of Furious Redemption, part of Truth's forces, inserted forces into the city of Cleveland in North America in search of a supposed Forerunner artifact. The UNSC managed to destroy one of the fleet's cruisers, the Harbinger of Piety and the Minister of Inquisition onboard, when a civilian injected with a tracking compound was taken to the ship for interrogation about the artifact.
Upon Truth's arrival the Dreadnought landed directly on the nearly uncovered artifact, allowing his fleet to cluster around the structure and set up a defensive perimeter. After the Master Chief joined up with UNSC forces, he spearheaded an effort that pushed the fleet's ground forces further towards their innermost stronghold - a mammoth Forerunner structure which served as the gateway to the Ark. However, they were too late to prevent Truth from activating the Forerunner structure.
 The Ark
After the Prophet of Truth activated the Portal, Truth's fleet went through the slipspace rift to the Ark, another Forerunner installation outside of the Milky Way Galaxy. Soon after this the Flood appeared, delaying the UNSC's pursuit of Truth's fleet. Truth's fleet used this time to deploy ground forces to the Ark, while Truth and his bodyguard of Jiralhanae moved to the Citadel to activate the Halo rings.
After the humans and Sangheili contained the Flood on Earth, a joint UNSC-Sangheili effort, consisting of at least two UNSC frigates, and the Fleet of Retribution, consisting of nine Sangheili cruisers and an assault carrier, managed to follow the Covenant ships a few hours after their initial retreat through the portal. Upon arriving above the Ark, Truth's Fleet engaged the Fleet of Retribution, backed up by the UNSC frigates. While Truth's fleet outnumbered the separatists three to one, the Separatists' tactics proved superior, eventually obliterating the entirety of Truth's fleet. Together with the total defeat of the Loyalist forces on the Ark itself during the Battle of Installation 00 and Truth's death at the hands of the Arbiter, this signalled the end of the Human-Covenant War.
During the opening cutscene of the Halo 3 level The Ark, a Sangheili onboard the Shadow of Intent states Truth's fleet outnumbers them 3 to 1. If this is correct, it means that during the Battle of Installation 00 Truth's fleet was approximately 30 ships strong.
 List of appearances
- Halo: First Strike (First appearance)
- Halo 2
- Halo: Ghosts of Onyx
- Halo: Uprising
- Halo 3
- Halo 3: ODST
- ^ a b Halo: First Strike, page 297
- ^ a b Halo: First Strike, page 333
- ^ a b c d e Halo Waypoint, "Ten Twenty"
- ^ Halo 3: ODST
- ^ Bungie.net: Bungie Weekly Update: 01/23/09
- ^ Halo 2
- ^ Halo: Uprising
- ^ Halo 3