AN: This is just here to give you a bit of background lore to this AU. If you feel like skipping it, please go right ahead. It shouldn't affect your reading experience or the story too much.

Timeline

2553

The Human-Covenant War, officially called the Great War, officially comes to an end. Hundreds of worlds burned, turned into glass through Covenant orbital plasma bombardment. Earth, the birthplace of humanity still bears the scars of war. The once proud UNSC navy once numbering in the thousands has been reduced to a mere few dozen ships. Billions of humans, both civilian and military alike are dead. The population dropped from 43 billion humans down to a mere 20 billion, the numbers of colonies have gone down from 180 planets down to just 17. Despite all the loss and suffering, humanity begins to rebuild.

The remaining UNSC ships are ordered to return to Earth to regroup and defend the portal leading to the Ark. A total of 59 ships are left with only a single Marathon heavy cruiser remaining, the rest are a mixture of destroyers and frigates.

The Elites, now recognized as the Sangheili, return to Sanghelios to rebuild themselves as an independent race. The Unggoy, Mgalekgolo, and Huragok all choose to remain with them. The Sangheili however, spent centuries as the warriors of the Covenant, and have lost their ways and knowledge of how to live as civilians. While they still retain a powerful and vast military, things begin to fall apart as maintaining such a force and kick-starting an economy proves difficult. The Sangheili as well as the races who left the Covenant, vow to never again take up arms against humanity ever again, and while they understand it will take time to humanity to trust them, they are willing to wait. The Arbiter, Thel Vadam, forms a new feudal government, with his equivalent of Lords, Kaidon's, forming a council to advise him. Though in effect, Thel Vadam remains as the Commander in Chief of the Sangheili military. His first order of business, eliminate the remaining Prophets and Jiralhannae strongholds scattered throughout the galaxy. The new Sangheili alliance with the former Covenant species is known as the Sangheili Union. The Unggoy, Huragok, and Mgalekgolo are listed as full citizens and aren't too bothered about the name of their new government.

On December 25th, 2553, Lord Hood formally relinquishes the UNSC's emergency powers back to the newly reorganized United Human Federation. The UNSC will continue to control all military aspects of the UHF, while the UHF will run the civilian governments responsible for Earth and her colonies. Humanity learns its lessons from the UEG, and this time respect the colonies wishes for a larger say in dictating policy. Every colony is granted a seat in the newly formed Senate, with each colony electing a senator to represent the Colony's interests. In addition to a seat in the Senate, each colony is given more autonomy over their respective colonies, this is to placate the populace and prevent another insurrection as before the Great War.

2554

The Sangheili military, after nearly a year of constant warring with the remaining Covenant strongholds, begins to fall into disrepair. The lack of a strong economy, as well as a lack of proper infrastructure and auxiliary units, prompts the Arbiter to approach the UHF with a desperate proposal. They would exchange technology such as shields, ship-grade weaponry and the rare but vital Huragok for human civilian experts to remodel their fledging economy as well as to establish a solid bureaucracy. Lord Hood, while still not trusting the Sangheili completely, agrees and orders the technology be studied and integrated into the UNSC fleet and army.

Vice Admiral Parangosky, the head of ONI, dies of natural causes. Commodore Veronica Dare is promoted to Vice Admiral and takes over. She immediately begins a purge of ONI, eliminating all those with die-hard loyalty to Parangosky's legacy. She reins in ONI's black-ops and after a long and heated debate with Lord Hood releases all information of the Spartan program to the public. While many are horrified with the decisions used by ONI, they all come to recognize the need and benefit of the Spartans. Vice Admiral Dare amends the Spartan program so that only volunteers from the armed forces may join, though it remains that if a child between the ages of 11-16 shows potential he/she may join if given consent.

On the anniversary of the ending of the Great War, an hour of silence is observed on Earth. The Arbiter dispatches representatives aboard the Union Vessel (UV) Forgiving Legacy, one of their last few CAS class assault carriers. Though distrust remains between the humans and the Sangheili, signs of rapprochement begin to show.

2555

The first of the new ships incorporating Covenant technology is produced. All UNSC ships now have energy shielding, plasma projectors, and torpedoes as well as pulse laser point defence systems. However, the UNSC has created a new weapon known as a PMAC or Plasma Magnetic Accelerator Cannon. The PMAC is similar to its predecessor, the MAC gun, the only difference is that when fired, the MAC round is encased in superheated plasma causing additional damage upon impact. Union technology increases the effective firing range of UNSC weaponry as well as their rate of fire. Despite the new technology, the UNSC opt to keep their beloved missile systems, replacing the ageing Archer missile with Howler and Rapier missiles.

2559

With an economy showing signs of growth, the Sangheili Union begin to expand and set up colonies, many of these colonies are on former Covenant planets with existing populations. They absorb them into the Union and begin using the revitalized Sangheili fleet to patrol their space.

The new flagship of the UNSC Navy, UNSC Infinity, along with her sister ship UNSC Eternity are commissioned into the fleet. Designed during the Great War with the intent of being pure weapons, they had every scrap of Covenant and Forerunner technology incorporated into them. Infinity and Eternity are given their own task forces with one objective: Find the remaining Halo rings and decommission them before they could fall into the wrong hands.

Lord Hood, along with senior members of the Admiralty, devise the "Hood Protocol". It puts into effect policy and courses of action to combat the Flood threat.

In April, UNSC Eternity stumbles on to a Dyson sphere at the location of the former ONI world of Onyx. There they recover Doctor Catherine Halsey and her team of Spartan II's and III's. Renamed Trevelyan, the sphere is turned into a joint UNSC-ONI research base, where engineers and scientists work to reverse engineer the treasure trove of Forerunner technology. The Spartans were given the option of honourable retirement from the military, or to stay on and train the next generation of Spartan IV's, all of them accept the latter option.

2560

While on a survey mission, the Union cruiser True Intentions discovers the UNSC Spirit of Fire. After boarding the vessel and waking the remaining crew from Cyro, Captain Cutter is convinced of the peace that now existed between them. With the lack of a spare slipspace drive, the Shipmaster of the True Intentions conducts one of the riskiest moves ever recorded and tows the Spirit of Fire through slipspace back to UNSC space.

The return of the UNSC Spirit of Fire is treated with as much pomp and circumstance as one could imagine. The crew is treated like heroes and Captain Cutter was promoted to Rear Admiral, the Spirit of Fire turned into a museum and is placed above Memorial Hill in Voi. This also leads to a new high in Union-UHF relations, and just 3 weeks later, the UHF and the Union sign a mutual military and technological alliance. It calls for the guarantee of each other's sovereignty as well as the promise to come to each other's aid in times of need. Minor details include further trade agreements and joint-fleet exercises.

2565

After the annual review of the UNSC Navy, Lord Hood orders the planning of a new set of fleet warships. These ships will incorporate the best of Union, Forerunner and Human technology.

After a miscalculation of slipspace coordinates on board the destroyer UNSC Reunification, it ends up in deep space. There it makes a shocking discovery. Sitting barely 500,000 kilometres from it was a massive space station. The station had the similar aesthetics of a UNSC station, only on a much larger scale. It's straight lines and blocky surfaces gave it an ugly, yet beautiful look. It almost resembled 2 Pheonix class Colony ships back to back, flanked by 4 Cradle class repair ships- 2 on either side. Jutting out from the centre of the station was a tall pillar. A ring ran around the pillar and was connected to it by 8 long beams. The size of the station is estimated to be at least 900km long, 500km wide and some 150 kilometres tall. The radius of the ring is recorded as some 150km.

After reporting this discovery back to HIGHCOM, Lord Hood dispatches the UNSC 5th Fleet to seal off the space surrounding the station. He also informs that President of the UHF who in turn informs the Union of this development.

Expeditionary teams are dispatched to the station to learn more about it. They discover the station had been built by the ancient Human Empire years before the Human-Forerunner War. Following the destruction of ancient humanity, the Forerunners occupied the station until their own destruction at the hands of the flood. It is assumed that the activation of the Halo array cleared out the station of all Flood forms. Nevertheless, Lord Hood orders every millimetre of the station scanned and cleared of all Flood presence, if there is any. A massive force of over a million men begins combing the enter station, involving the UNSC First and Second Army groups and all the Marines attached to the 5th Fleet.

The Sangheili Union finally declares victory over the Jiralhannae and the Prophets. The Prophets have been rendered extinct, their kind wiped out. The Jiralhannae were eventually pushed back onto their home planet of Doisac. They were stripped of all advanced technology and eventually they resulted in warring amongst themselves on their home planet. A small flotilla of 8 Union ships remains in orbit over Doisac to watch over them, to prevent them from rising up once again.

2566

The space station found the previous year, after being painstakingly scanned for any flood presence is finally given the all clear by the UNSC. Dubbed Bastion by the troops, the name sticks, and the station is officially given that designation. After much discussion with the UNSC High Command, Bastion will be turned into the third most important military asset after Earth and Reach. It will also act as the command and control centre for UNSC fleets operating in outer UNSC space.

Workers and personnel begin renovating the station for UNSC, while strategists begin to plan defences for the soon to be shipyards.

2580

15 years after it's discovery, Bastion is commissioned into the UNSC military. As a shipyard as well as the command and control centre for several UNSC fleets, it's security is of the utmost importance. At all times, a fleet of ships will be stationed there to supplement the Super PMAC platforms in the security of the station.

2590

More than 30 years after Lord Hood ordered a new breed of UNSC warship, the project is completed:

The Charon class frigates are modernized with new weaponry, armour, and shielding. The famed Paris class frigate is to be retired from frontline service, and used for logistical support; the larger more modular Eridani class frigate replaces them.

The Warhammer class destroyers replace the ageing Halberd Destroyers. Supplemented with a PMACs, Howler, and Rapier missiles, TYR tactical nuclear missiles, and a pulse laser defence system. New technological advances allow for a much more efficient plasma fusion reactor to serve as the primary power source, allowing for faster speeds and recharge rates to be achieved. The ship is armoured in almost 8 metes of new Titanium AA plating, which allows for incredible amounts of punishment to be received.

Replacing the old but reliable Halycon light cruisers are the Whitcomb light cruisers. Taking inspiration from the UNSC Pillar of Autumn, the Autumn class cruisers are developed and fulfil the role of the UNSC's new heavy cruisers. The Marathon and Valiant class cruisers are phased out in favour of the new Keyes class Super Heavy Cruisers, though designated as command ships they could still pack a punch and hold its own in a fight. A subclass of the Keyes class is developed called the Poseidon class; they are pure ship killers, sacrificing speed and some offensive weaponry for a more powerful super PMAC on the bow.

The Cradle class Mobile Repair Docks were replaced with the Epirus class Mobile Repair Docks (MRD), these were much larger than their predecessors and its modular repair docks could be easily customized to fit any ship in the fleet.

4 new classes of ship were conceived: the Cole class battleships, the Vindicator class heavy fleet-carriers, the Armageddon class battle-cruisers, and the Dauntless class dreadnoughts. It is estimated that it will take 12 years to replace all current UNSC ships and an additional 8 for the new fleet expansion program with shipyards running around the clock.

January 2592

The UHF surpasses the number of colonies they had before the Great War and begin to temporarily halt all colonization efforts in order to further consolidate their position.

UNSC armed forces reach an all-time high. The Home Fleet, at a staggering 900 ships defends Earth and the Sol System. With another 30 fleets spread out over UNSC space. The navy reaches over 12000 vessels in active service.

ONI commissions the Gobi class prowler, a replacement for the ageing Sahara class. Including all the latest developments in technology, the Gobi had the ability to remain cloaked for an indefinite period of time while reducing its ability to be detected. The Gobi class, in theory, had the firepower of a destroyer, but it was considered to be the last resort option only.

The colony of New Madrid discovers an object of unknown origin at the system's edge. Once encased in ice, it was identified as a dwarf planet by sensors. However, reports from the planetary defence fleet indicate that it is given off 'strange' readings that the sensors could not identify. It's shaped resembled that of a tuning fork, a 20km long tuning fork.

The UNSC 8th Fleet, operating out of Bastion, deploys for joint fleet exercises with the Union 5th Fleet, to test tactics and unit cohesion. For this, they are deployed to a newly colonized system on the fringes of UHF territory known as New Geneva.