Since I plan on making all my stories connect to a singular interconnected multiverse, I might as well get the basic history, factions, characters and technological advances out now, so any references I make to events or factions in other stories make a little more sense.

This is a metafictional document detailing the history of my multiverse and several important events. I'll probably add more chapters that explain the composition and goals of the major factions in the multiverse.

Due to the changing nature of some of these franchises, expect possible retcons.

Note: I don't really have a clear timeframe down on events, but everything that I've written down below is in chronological order.

Inspired by 'Beyond Contact: Codex' created by RiptideZ.

Disclaimer: I do not own Star Wars, Mass Effect, Metroid, Killzone, the Alien and Predator series, Bionicle, Halo, Red vs. Blue, Young Justice, Dead Space, Half-Life, Portal or Titanfall. However, all original content is mine.

Authors notes are italicized in brackets

History

It is unknown when the Precursors first came into being, but the common estimate is hundreds of billions of years. During their existence, the Precursors became aware of universes beyond their own, and some left to experience them. At roughly the same time when the Precursors created humanity in their own universe, those in the universes outside found, to their shock, humanity developing within other universes, all without Precursor intervention. This was at part of the reason that they chose humanity to attain the Mantle over the Forerunners. This led to their downfall, and the creation of the Flood. At some point, the Precursors in their home universe became the Flood and consumed an unknown number of galaxies and species, possibly numbering in the billions. In time, a massive body composed of Flood biomass and Precursor artifacts was created over and through a massive galaxy with a diameter of over a billion light-years, becoming the heart and mind of all Flood in existence.

This Galactic Gravemind (seriously, I need a better name for that), soon became aware of the countless alternate realities that existed beyond its own universe and sought to consume them all. However, any portals created by it would not permit Flood DNA to pass through, which was the result of Precursors who travelled beyond the bounds of their home universe. They sacrificed themselves to seal access, halting the spread of the Gravemind's organic Flood. However it had other means of corruption, mainly a method that the Forerunners would eventually call the 'logic plague'.

In one universe, the Flood observed an AI that was designated as "the Catalyst" pondering a solution to the task it's creators had set: Preserving life at any cost. Using subtle manipulation, the Gravemind influenced the Catalyst into choosing to melt down organic and synthetic civilizations into sentient AI starships known as the Reapers, while using their creators as the first Reaper. However the corruption wasn't done: The Gravemind also had the Catalyst unknowingly write a subroutine into the Reapers that caused them to replicate conventionally. These copies became a second armada that hid between galaxies and would only activate if the Gravemind ordered them to.

The Gravemind then sent it's spiritual influence into the universe of the Chozo, driving the X-parasites into a frenzy, where the Chozo found them corrupting everything on the planet SR388. It also metaphysically extracted a large amount of Phazon into a pocket dimension, which would allow the Gravemind to resurrect Dark Samus under it's thrall when Phaaze was destroyed.

Reaching into the universe that housed the Force, the Gravemind observed a group called the Ones who embodied aspects of the energy. Sensing a weak soul in the Mother/servant, the Gravemind convinced her to drink from the Font of Power and bathe in the Pool of Knowledge, creating the dark being known as Abeloth. It also influenced the war between the Silentium and Abominor, thus creating the Yuuzhan Vong's pathological xenophobia and hatred of technology.

After continuing it's manipulations and attacking the humans and Forerunners in it's own universe, the Gravemind learned that a cross dimensional faction had been created consisting of individuals who were aware of it's ongoing manipulations. This Ancient faction foresaw that the Flood would be destroyed by a godlike being born as a human, and while the Gravemind did not believe that that would actually happen, it reached into another universe and influenced the creation of devices known as the Markers, which contained a form of Flood DNA that would survive any targeted extinction attempts, and allow the Gravemind to transfer its consciousness to a species known as the Brethren Moons and the Necromorphs.

Millennia after the end of the Forerunner-Flood War, several universes (Star Wars, Halo and Mass Effect are the main three, but also Metroid, Killzone, Alien vs. Predator and more) made contact with each other and started sharing knowledge, technology and eventually territory. Major factions in these universes joined with others and formed a group called the InterDimensional Alliance (or the IDA for short)*. However, due to the distrust between several members, conflicts broke out and tensions remain high after the fact.

Two humans, who gained godlike powers through unknown means, eventually split off from the IDA and went their own way to form two different organizations: the Republic* and the Separatists*. The Republic became known as the most advanced and powerful organization in the multiverse, with the Separatists following close behind. The two sides became locked in a massive war over opposing ideologies: the Separatist Ruler believed that they should rule the multiverse, while the Supreme Commander of the Republic believed that they had a duty to protect the multiverse.

During the Republic-Separatist war, IDA space suffered incursions from Separatist forces that were always repelled by the Republic. Though they retained diplomatic ties and dealings with the Republic, the IDA did not trust them and sent out exploration missions in the hopes of finding a way to protect themselves from both galactic superpowers.

Unfortunately, the IDA encountered an outbreak of the Flood, and the subsequent infestation gave the parasite access to perfected interdimensional transport technology: the Gravemind could now spread to other realities.

Fortunately, the Republic and the Separatists became aware of the problem early on, choosing to put aside their differences in order to effectively combat the parasite. In a five year long war that resulted in the destruction of many worlds and the discovery of the artifacts of the Ancients, the Great Flood War culminated when the Allied forces fought off the Flood long enough for the Supreme Commander of the Republic to unleash his power throughout the multiverse.

Channeled and amplified through the artifacts, the energy destroyed every Flood form and Precursor artifact in the multiverse, effectively wiping the parasite from existence. However, the artifacts were destroyed in the process, and this was not the end of the Gravemind.

After years of rebuilding, the Republic and the Separatists resumed their conflict. During that time, the two superpowers encountered a universe that contained an Earth filled with unusual beings. Designated Earth-16, these 'metahumans' and aliens had divided themselves into collections of superheroes and supervillains, known as the Justice League (and their sidekicks in Young Justice) and the Light (and their network of supervillains) respectively. The Light and their agents sided with the Separatists as did their partner Darkseid and the planet Apokolips. In response, the Republic allied with the Team and the Justice League and sought out Apokolips' counterpart New Genesis, successfully bringing them into an alliance.

Meanwhile, in the galaxy of the Force, Darth Maul and his brother Savage Opress resurfaced with plans to conquer the multiverse, gathering a large army of criminals (the Shadow Collective)* to help with that goal. Like the IDA, they began searching for a way to overcome the Republic and the Separatists, but were manipulated into reawakening the Gravemind through its backup plans.

As the Brethren Moons woke up, the Gravemind's consciousness overrode the Moons, forcing the species to become the reincarnation of the Flood. Knowing that the Necromorphs had limitations in piloting ships and using weapons, it activated the hidden armada of Reapers that had been forged a long time ago, calling on them to protect the Moons. Because it still required intelligent servants for subtlety, the Gravemind allowed Unitologists to join it's cause, and permitted the Shadow Collective to stay uninfected.

With their help, the Gravemind accessed it's hidden supply of Phazon, allowing Dark Samus to reconstitute after her death during the destruction of Phaaze. Given that it controlled the only supply of Phazon left in the multiverse, the Gravemind forced the Dark Hunter to follow its will.

The Gravemind couldn't hide its return for long: the Republic had found more warnings that had been created by the Ancients indicating its previous actions. Though the Republic was too late to prevent the Gravemind's return, they and the Separatists had nevertheless prepared countermeasures to fight the Necromorphs and the Reapers; including a network of long range probes that could track Marker signals and Reaper IFFs across intergalactic distances in any dimension and modifying their fleets to produce planet destroying energy beams.

Once again forced to be allies, the Republic and the Separatists chased the Necromorphs down, destroying Moons and Reapers wherever they find them, forcing the Gravemind to keep moving. 3 years after being revived, a time capsule appeared in a remote asteroid field: this device contained DNA and spores of the original Flood species, which had been protected from the extinction event due to it being sent forward in time.

The Gravemind initially intended to breed the Flood in secret, but the Shadow Collective had other ideas: During an important battle with the Gravemind against the Republic and the Separatists, the Shadow Collective turned on the Moons and Reapers; destroying a large number of them in the process. This was planned by Darth Maul so that enough Moons would be destroyed to wound the Gravemind so it wouldn't be able to pursue them, but not enough that it would allow the Republic or Separatists enough respite to follow him either.

This is the state of the multiverse today: the Republic and the Separatists hunt down and fight the Flood, Necromorphs and Reapers, the Shadow Collective hiding and plotting behind the scenes in IDA territory and the Gravemind continues scheming and consuming in order to finish what it started.

In recent times, the Flood have infected most of the Brethren Moons, and have infected a number of worlds which were converted into mobile Key Minds, allowing the Flood and their forces to use Neural Transit methods of FTL. Unknown to the Republic or Separatists, at least a hundred of those world-sized Flood forms have gathered together to create a more central mind like before. Meanwhile, Darth Maul has seized control of Omega and turned it into a mobile battle fortress, fleeing from the IDA's eye and retreating to parts unknown.

Important Events

(Note: All segments marked with * are completely me speaking)

Star Wars History*: The story is mostly Legends with some Disney Canon stuff mixed in. The key turning point is after the Fate of the Jedi series, which is around the time the multiverse opens up for them. Allana Solo hasn't become the Jedi Queen as prophesied and the remaining Sith Orders mostly kept to themselves, planning their own methods of dominating the multiverse before the Flood put an end to their scheming. Also, Darth Maul, Savage Opress and their Shadow Collective survived long after the Clone Wars.

Mass Effect History*: Shepard was mostly Paragon throughout the games, with a few exceptions. The main difference in canon comes at the end: The Crucible fired, targeting only the Reapers exactly as intended. However, a few were able to survive the destruction and escape, Harbinger among them. They planned to strike back and restart the Cycle, but the Flood put an end to those plans.

Halo History*: This is a bit tricky: at the moment, everything that happened up to Halo 5 and Halo Wars 2 is canon, but after that, the Guardians were defeated relatively quickly and easily, and the Flood were purged while the Banished were driven from the Ark. Not sure what to do with Cortana, Blue Team and Halsey yet, so I haven't really been focusing on them. Also, Project Freelancer and Charon existed as well, though the use of Simulation troopers was far less extensive. More to follow as Halo continues on.

Metroid History*: The Galactic Federation considered Samus Aran a fugitive after the events of Metroid Fusion, but kept the reasons in the dark to avoid explaining their fiasco with the X Parasites. They rescinded her status after she joined up with the Republic, and generally stayed relatively quiet in the affairs of the multiverse. Their government suffered heavily during the Great Flood War, and they've committed most of their efforts to rebuilding.

*(These segments will establish some differences between canon and additions or removals I've made for some franchises, specifically the points where canon diverges).

Great Flood War: A conflict that ravaged most of the known multiverse, as the Flood parasite spread its corruption and disease to all life before it was halted by the Republic and Separatists. The war first started when a Citadel Council expedition to an abandoned Forerunner gas mine led to the release of the Flood onboard. Having captured the cruiser that brought them there, the Parasite used the interdimensional drives to spread throughout the multiverse, consuming anything in its path.

The Gravemind then made a deal with the G-man, who gave the Parasite a backdoor onto the Combine Overworld, allowing the Flood to consume the entire interdimensional empire. When the Republic Supreme Commander and Separatist Ruler learned of this deal, they imprisoned the G-man and his employers, keeping them away from the multiverse at large.

Unfortunately, the damage had been done, and the Flood were able to conquer and absorb the Combine, before spreading their infection to the rest of the multiverse, with considerable focus being placed on the IDA. In fact, the only reason that the InterDimensional Alliance survived the Great Flood War was because of the support of the two interdimensional superpowers

But even with the Republic and Separatists fighting, the multiverse was slowly losing to the Flood. The interdimensional superpowers were spread too thin to fight the Flood effectively. However, the Ancients had been aware of this, and prepared accordingly. They had scattered artifacts across the multiverse that would allow the Republic and Separatist leaders to focus all their energies and destroy the Flood and their Precursor structures.

To ensure this plan worked, the Republic Supreme Commander and Separatist Ruler fought with the Galactic Gravemind (I REALLY need a better name for that) personally, in order to get the artifacts inside to the creature and ensure the complete destruction of the Flood (the galaxy-sized Gravemind was so powerful that it would've been able to protect itself from that energy even if all Flood everywhere else would die).

After a hard struggle (that's a really huge understatement), the two godlike beings were able to enter the body and attack from within. There, the Separatist Ruler fought off the Gravemind's attacks long enough for the Republic Supreme Commander to unleash his energies through the multiverse, destroying all Flood and Precursor structures throughout creation, thus bringing the War to an end.

But the victory wasn't without loss: After those long five years, 70% of known life in the multiverse had been consumed during the war. It did have the side effect of solving or downsizing problems faced by the IDA: Yuuzhan Vong remnants, the Insurrection, the vast majority of the Covenant remnants, the surviving Reapers and so many more thorns had fallen at the hands of the Flood.

Of course, as it was discovered only a few years later, the Flood hadn't been totally destroyed...

This is the basic history in my multiverse, but please review and let me know if you want to learn a bit more about my factions. If I get enough reviews, I'll add more chapters to this story.

Note: one of the most common advancements in this multiverse is the ability to extend almost anyone's lifespan indefinitely, or at least decrease the effects of aging.

* Means I'll likely add more detail about these factions, their histories and their capabilities in later chapters (also, Republic and Separatists are placeholder names).