Assassination of the Prophet of Regret

The Assassination of the Prophet of Regret was an operation carried out by UNSC forces from the  to assassinate the Covenant High Prophet of Regret on November 2, 2552, after following the Prophet's assault carrier Solemn Penance from Earth to Installation 05.

Background
Following his discovery of the location of the portal leading to the Ark, a facility that would allow the Covenant to fulfill their "Great Journey", the High Prophet of Regret took a hastily-assembled fleet of fifteen vessels to the planet, unaware that it was the homeworld of humanity. The fleet arrived on October 20, 2552 and was immediately engaged by the vastly numerically-superior UNSC Home Fleet. As the Fleet of Sacred Consecration fought a losing battle over the planet, Regret took his flagship, the Solemn Penance directly down to the city of New Mombasa in eastern Africa. The Prophet deployed ground troops into the city to search for the location of the Ark's portal. Eventually, as human ground forces closed in on his carrier's landing zone and UNSC vessels prepared to deploy forces onto the carrier from above, Regret initiated a slipspace jump while still over the city, using information he had learned from the Luminary recovered from Meridian to plot a course for Installation 05.

Despite being caught off-guard by the Prophet's sudden departure, the UNSC, captained by Commander Miranda Keyes was close enough to pursue the assault carrier. After being given permission from Fleet Admiral Hood, the In Amber Clad, with Spartan John-117 and Sergeant Major Avery Johnson onboard, followed the departing Covenant carrier as it transitioned into slipspace near the city's space elevator. Several UNSC vessels followed the pair into slipspace using the assault carrier's wake, but became separated from the Solemn Penance and In Amber Clad.

The battle
"Avery Johnson"

- Cortana

The Solemn Penance exited slipspace on November 2, 2552, arriving in close proximity to Installation 05, orbiting the gas giant Substance in the Coelest system. The Prophet of Regret took Solemn Penance down to the surface of the ring, deploying large numbers of ground troops and armor into a network of Forerunner ruins. The Hierarch fortified himself within a temple in the middle of a large lake and began to sermonize to his loyal forces, declaring his intent to activate the installation and begin the Covenant's "Great Journey".

Meanwhile, Commander Miranda Keyes of the, trailing behind the assault carrier, opted to keep a low profile to avoid detection by the far more powerful. She realized the importance of discovering why the Covenant had attacked Earth as well as their arrival at the Halo ring and designated the capture or killing of the Prophet of Regret as their primary objective. She ordered John-117 and a platoon of Orbital Drop Shock Troopers from the 7th Shock Troops Battalion to deploy via M8823 SOEIV to secure a landing zone to Sergeant Major Avery Johnson to deploy more ground forces to support them. As the In Amber Clad made a pass over the ring, the frigate deployed a dozen SOEIV pods. While most survived to enter the atmosphere, Covenant ground forces had deployed a number of Shade turrets in the landing zone that opened fire on the pods as they neared the surface. Several pods were struck and destroyed and many ODSTs were immediately killed by Covenant troops upon leaving their pods. Ultimately only four UNSC personnel would survive to make landfall-John-117 and three ODSTs. Wielding a rocket launcher, the Spartan destroyed the Shade turrets and led the surviving ODSTs into a nearby Forerunner structure. The four secured the ruins and managed to hold off several Phantoms and their complements of infantry, allowing Sergeant Johnson to approach in a Pelican to deploy a Warthog for the team. As the Pelican approached the landing zone, Johnson spotted the structure in the lake that the Prophet of Regret had taken refuge in and notified the team of its location.

John-117 and his team commandeered the Warthog and set out toward their objective, wiping out a camp of Kig-Yar snipers before arriving in a large area fortified by the Covenant, who retracted the bridge spanning a nearby gorge. Knowing that the Covenant intended to hold them down, Cortana informed the team that the controls to extend the bridge were in a nearby structure. The team was forced to contend with more Shade turrets, infantry and Ghosts around the bridge structure while a pair of Wraiths on the other side of the canyon began to bombard the UNSC forces with their plasma mortars. The team managed to fight their way into the structure and extend the bridge, but the presence of the Wraiths necessitated the deployment of a Scorpion tank. Johnson's Pelican arrived with the armor and the Master Chief mounted up, using the Scorpion to destroy the two Wraiths, as well as a flight of Banshees that attempted to stop them. The UNSC force pushed into a larger series of Forerunner ruins, destroying large numbers of Ghosts, Shade turrets, plasma cannons and groups of infantry until they finally emerged into an open area with another large structure. One of the ODSTs informed John that another Pelican was coming in to drop off more ground forces and weaponry. After clearing a landing zone, the Pelican dropped off a number of ordnance pods and more Marines. In response, Covenant troops flooded out of the structure, attempting to halt the humans. Forced to leave the Scorpion behind, John-117 and his team fought furiously against the Covenant occupiers, managing to push into the structure. Here they encountered a hologram of the Prophet of Regret, Cortana translating some of his words for the Spartan. John continued to push forward, engaging a small group of Covenant before passing through a narrow cave and emerging into a larger area with a waterfall and numerous Kig-Yar snipers on station. The Chief made his way through the area, fighting back the Covenant forces including several swarms of Yanme'e that attempted to ambush him. He eventually made it to the first structure in the lake, the exterior of which was guarded by more snipers and Yanme'e. John made his way inside, where he encountered members of the Covenant Honor Guard. After a tough fight, John managed to slay the Honor Guardsmen and secure the structure. As the Master Chief made to leave the structure, Cortana called for him to stop near a holographic projection of the Prophet of Regret. She confirmed that Regret was planning to activate the installation to John, translating the sermon into English. John radioed Commander Keyes about the situation. Keyes, after studying the information Cortana had acquired from Installation 04, knew that the Prophet would need the ring's Index to activate the installation. Having located the Library where the Index would be housed, and determined to deny it from falling to the Covenant, Keyes ordered Johnson to extract his men and rendezvous with her at the Library. Now armed with all the intel that the UNSC would need, Keyes ordered John-117 to assassinate the Covenant Hierarch.

Before John could leave the structure, he and the two Marines accompanying him were attacked by a swarm of Yanme'e descending from above. Managing to fend off the insectoid Covenant soldiers, the team arrived outside, where more Covenant including a number of snipers attempted to stop them. The team fought across a small bridge into more ruins, clearing out a room full of Unggoy and Kig-Yar before emerging into a circular arena where more snipers and Sangheili marksmen were stationed. Eventually clearing the area, the team only had a brief moment of respite before a Phantom flew in, deploying a Mgalekgolo pair onto the platform. After a struggle, the Master Chief managed to slay the gestalts, allowing a Pelican to drop off reinforcements and resupply canisters for the team. Cortana warned the team of a goldola packed with Covenant troops approaching from a structure further out in the lake. The UNSC forces dug in and managed to eliminate all the Covenant on the gondola. Opting to use the gondola, the team were forced to repel a swarm of Yanme'e and another gondola with Covenant troops. As they approached the structure, snipers and Shade turrets opened fire on the UNSC forces, but soon fell. John and the Marines engaged a large group of Kig-Yar and Yanme'e around an elevator shaft. Cortana informed the Spartan that the elevator would carry them to the structures further out in the lake. As the elevator approached, containing a trio of Kig-Yar, the UNSC forces prepared an ambush. Taking advantage of the tight quarters in the elevator, the team quickly slew the Kig-Yar and entered the elevator car. As the elevator carried them under the lake, Cortana intercepted a transmission on the proselytization network from Regret's assault carrier to the Prophets of Truth and Mercy in High Charity. The Prophet of Regret expressed his forgiveness for his rash attack on Earth, arguing that he was unaware of the human presence on the planet or its status as humanity's homeworld, something Cortana considered odd-in reality a fact purposely withheld by the Prophet of Truth from his fellow Hierarchs.

Upon arrival at a the next structure, the team made their way forward, eliminating a group on Unggoy in a submerged corridor before arriving in a large chamber where Sangheili Honor Guardsmen, snipers, Yanme'e and another Mgalekgolo pair all fought to halt the progress of the UNSC forces. After a protracted battle, John and the Marines secured the entire chamber. They moved into another submerged corridor, killing a unit of camouflaged Covenant troops before arriving at another elevator. Here, Cortana intercepted the response from the Prophet of Truth to Regret, chastising the younger Hierarch for his actions and telling him that he had only avoided a public display of contempt was due only to the Prophet of Mercy. While Cortana noted that killing Regret would likely destabilize the Covenant leadership, she considered that it might actually be a favorable outcome for the Prophet of Truth. The team left the elevator once it arrived at it's destination, catching a pair of Honor Guardsmen and several dozing Unggoy off-guard. As they emerged from the structure, a pilot informed John that his Pelican was nearly out of fuel and he was only able to make one final supply run. Now rearmed and reinforced with several more Marines, the Chief pushed into another set of ruins occupied by Covenant forces. A Phantom arrived to drop off another lance of Covenant but they soon fell to the human onslaught. Finally the team arrived at the gondola that would take them to the final temple where Regret was holed up. Commander Keyes radioed the team, asking for a status report, to which Cortana affirmed that they were almost to their objective. Keyes and her forces had been stopped by an energy barrier around the installation's Library and were trying to find a way to bypass it but she promised to keep the team informed of their progress. The team's gondola was strafed by several Banshees and attacked by Sangheili Rangers but they managed to fend off all attacks as they crossed the lake towards the Prophet of Regret's temple. As they approached, a group of Unggoy and Kig-Yar rushed out to man Shade turrets but they were soon dispatched. As John stepped off the gondola, High Charity and it's massive defense fleet exited slipspace high above the installation. As the Master Chief watched, Cortana stated that this was the largest Covenant fleet ever seen by humanity, before telling the Spartan to finish off Regret before they could intervene.

A group of Covenant rushed out of the main entrance to the temple, deploying plasma cannons to stop John and his two remaining marines. The Spartan fought his way into the structure as Cortana warned him that the fleet had launched waves of Phantoms towards the temple. With his time running out, John emerged into the temple's main chamber, where the Prophet of Regret himself waited, surrounded by his Honor Guard. Quickly realizing that the Prophet's gravity throne projected an energy shield too powerful to attack with conventional weaponry, the Spartan opted to physically board Regret's throne and beat the frail Prophet to death, while the two remaining marines engaged the Honor Guards. As the lifeless Prophet of Regret tumbled to the floor and his throne exploded, Cortana warned John that the Phantoms had been withdrawn and the fleet was preparing to fire on the temple. John sprinted out of the temple and began to run as Shipmaster Rhul 'Salmutee had the Solemn Penance target the temple with the assault carrier's energy projector in an attempt to kill the Spartan. John barely managed to escape, leaping into the lake as the temple was completely destroyed. As he drifted through the water, a large tentacle belonging to the Flood Gravemind ensnared the unconscious Spartan, and took him captive. The remaining marines were either killed in combat or by the blast from the carrier's energy projector.

Aftermath
The death of Regret allowed the Prophet of Truth to consolidate his grip on the Covenant. Using the death of the Hierarch as an excuse to discredit the Sangheili, Truth ordered a restructuring of the Covenant Honor Guard, casting the Sangheili out and replacing them with the Jiralhanae. While eavesdropping on a meeting between the Prophet of Truth, the Prophet of Exquisite Devotion and the Chieftain of the Jiralhanae Tartarus, Zo Resken, Truth's Second Administrator, overheard the three as they discussed their plans to elevate the Jiralhanae above the Sangheili, and later received news from G'torik 'Klemmee revealing that Truth had deliberately withdrawn the Phantoms sent down to reinforce the Prophet of Regret to ensure his death at the hands of the Master Chief. This was but one part of a "divisive mandate" that Truth had set in motion years prior. Secretly, he had devised a complex scheme, one which would soon culminate in the Great Schism, with the Sangheili being forced out of the Covenant. This would ultimately result in the deaths of the remaining Hierarchs, and the complete fragmentation of the Covenant during the Battle of Installation 00 a month later.

John-117 would be brought into the Gravemind's lair deep below Installation 05's Library, where he would come face-to-face with Thel 'Vadamee, Arbiter of the Covenant and the former Supreme Commander of the Fleet of Particular Justice, as well as the installation's monitor, 2401 Penitent Tangent and the reanimated corpse of the Prophet of Regret. The Gravemind brought the four together in order to explain the truth behind the Halo Array's function to 'Vadamee. When both John and the Gravemind's words failed to sway the Arbiter, the Gravemind opted to show the Sangheili for himself. Instructing the Chief and Arbiter to seek out the Activation Index, the Gravemind manipulated the ring's teleportation grid to teleport John-117 into High Charity while Thel 'Vadamee was sent to the cliffs near the installation's control room.

List of appearances

 * Halo 2
 * Halo: Broken Circle
 * Halo 2: Anniversary
 * Halo Mythos
 * Halo: Official Spartan Field Manual