Battle of the Prototype Halo installation
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During the Fall of High Charity, the Minister of Preparation, Boru'a'Neem, convinced Prelate Tem'Bhetek that his family was lost and got him to abandon the city without trying to save them. The Prelate subsequently blamed their deaths on Shipmaster Rtas 'Vadum who had part of High Charity glassed in a failed effort to contain the Flood. However, unknown to the Prelate, Vadum had only glassed the city after it was clear that it had fallen to the Flood and had first tried saving any San'Shyuum he could without success. As a result, Preparation had lied to the Prelate to get him to abandon the city and his family had most likely been alive at the time.
Enraged by 'Vadum's apparent culpability in the death of his family, the Prelate formed a faction led by himself and Preparation and made up of Yanme'e and Jiralhanae to get revenge, using the Prototype Halo installation located in a hidden sector of the galaxy as his base against the Sangheili. Unknown to the Prelate, Preparation had his own plans, intending to use the CAS-class assault carrier Shadow of Intent's reactors to power the installation to wipe out Sanghelios and all life in its star system. To this end, the Prelate attacked Rahnelo and captured the kaidon and his two sons to test the installation with.
The Prelate later ambushed the Shadow of Intent with his CRS-class light cruiser Spear of Light above Duraan with the intent of capturing the carrier and exacting revenge on 'Vadum. However, the Prelate was wounded and captured while his Jiralhanae forces were wiped out. From the captured Spear of Light's navigational database, 'Vadum and his crew were able to track the Prelate's base back to the installation in the hidden sector though he refused to tell them what was there. 'Vadum revealed the truth about what happened when High Charity fell, planting doubt into the Prelate's mind about Preparation's truthfulness. Before making a slipspace jump to the hidden sector, 'Vadum had most of his crew disembark to Duraan so as not to risk their lives.
Recognizing the danger of entering the hidden sector blind, Rtas 'Vadum chose to have the Shadow of Intent emerge from slipspace far outside the volumes of the Spear of Light's arrivals and departures. Rather than approach in the carrier, which had mostly non-functioning weapons due to its earlier battle, 'Vadum had the ship piloted by its computational matrix while he and his skeleton crew watched from two Phantoms. When Shadow of Intent entered the range of the Prototype Halo installation, Boru'a'Neem fired it at the empty ship. As the crew was not aboard, they survived, but enough of the energy wave struck the Phantoms that their minds were scrambled and the crew was left incapacitated, including Vul 'Soran. Taking advantage of that, Tem'Bhetek managed to escape his bonds, disable 'Vadum's Phantom and escape towards the installation. With the majority of crew too incapacitated to help, 'Vadum decided to go after the Prelate with only Tul 'Juran accompanying him. 'Vadum ordered that if his signal went dark, Stolt was to command the carrier to destroy the installation.
After escaping the Sangheili, the Prelate contacted his faction and warned that it had been a trick, demanding that the ring be prepared to fire again. Having managed to avoid the worst of the firing's effects, the Prelate chose not to spend time explaining what had happened to Preparation and demanded that the ring be prepared to fire again once he had reached the safety of the control bunker, but Preparation warned that it would be fired again when he chose and whether or not the Prelate had reached safety or not. Having seen 'Vadum's genuine remorse for what had happened to the Prelate's family and recognizing that most of Preparation's descriptions had been about the loss of his Sacred Promissory, the Prelate's suspicions and doubts continued to grow.
When the Prelate reached the test chamber, he discovered Preparation with at least two dozen Yanme'e armed with plasma pistols and needle rifles. Preparation claimed that the weapons were in case the Prelate didn't come alone and drew his throne back with its energy shield engaged when the Prelate tried to approach. Preparation warned that the ring was unstable and would not survive another firing. As such, Preparation refused to fire it again until it had reached its final target: Sanghelios. the Prelate realized that Preparation intended to use Shadow of Intent's reactors to charge the ring which Preparation confirmed, stating that they need only increase the power by twenty percent to be able to wipe out all life in the Sangheili home system and set the species back for ages to come. Preparation recognized that the Prelate was not as committed as he once was as their motion trackers showed the approach of 'Vadum and Tul. the Prelate demanded to know the truth about his family's death and realized that 'Vadum had been right from Preparation's response. Preparation explained that he had needed the Prelate's blind rage to see his plan through and exact revenge for the loss of his Sacred Promissory.
With the Prelate having turned against him, Preparation warned that there were many others who had escaped the Fall of High Charity who, full of rage or hungry for glory, would gladly take the Prelate's place. Preparation had the Yanme'e fire at the Prelate, but 'Vadum and Tul finally arrived as they opened fire. Tul threw her energy lance and knocked Preparation's shield off-line which allowed 'Vadum to hit him between the base of his neck and right shoulder with two shots from a carbine, mortally wounding Preparation who fled into the lift to the control bunker and sealed the door behind him. However, the Prelate was hit with a wall of Yanme'e fire which collapsed his own shields and mortally wound him.
The two Sangheili quickly turned their attention to the Yanme'e, attacking them with 'Vadum's carbine and a dropped plasma pistol respectively. Running out of ammunition, 'Vadum covered Tul while she retrieved her lance and acknowledged the danger to his species from the Halo ring if he lost, having overheard the discussion between the Prelate and Preparation about Preparation's plan. As the two attempted to reach the bunker's door controls, Preparation powered up the ring to destroy his enemies in a final act of revenge with not even the Yanme'e able to open the door. However, the Prelate, now knowing who had truly betrayed him, retrieved a satchel of plasma grenades from a Yanme'e corpse and wrapped it in his anti-gravity belt. Recognizing what the Prelate was doing, 'Vadum quickly fled the installation with Tul while the Prelate dropped the activated satchel of grenades down the shaft to the installation's power systems. The detonation destroyed the entire installation before the ring could fire again, forever eliminating its threat. The Prelate, Preparation and the Yanme'e forces were all killed in the explosion as well.
After returning to Duraan, most of the Shadow of Intent's crew either recovered on the planet's surface from their injuries or enjoyed the hospitality of the grateful residents. Rtas 'Vadum contacted Thel 'Vadam to report on the mission, stating that after the explosion, the crew had scanned every fragment of the debris field, but found nothing left of the Prototype Halo installation to recover. Though the crew had been left in bad shape from the ring's firing, they were all recovering well. Thel also agreed to revoke old naval regulations that prevented females from joining so that Tul 'Juran could join the Shadow of Intent. Having discovered clues pointing to a sizable flotilla of surviving San'Shyuum in the Spear of Light's navigational database, 'Vadum chose to seek it out to find those who deserved punishment as war criminals while separating out those who did not despite Thel's suggestion that he could retire and enjoy peace.
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