I Do Not Own Anything Halo Or Mass Effect, Just This Made Up Story ;)

Authors Note : This Story, or for the time being Timeline. Will show the baseline for the Alternate Universe. Some of it is Canon from both Universes and some of it is changed. Some small, some large. Just a warning in case someone starts moaning...

Edit : I have slightly changed the time-line to include the Unggoy as a Systems Alliance species, alongside the newly constructed Scarab's. I also gave the Council a larger fleet as the Systems Alliance has better technology and ships. I also fixed the issue with the Citadel and Mass relays, they have been there longer than the Precursors. Hope you enjoy ;)

Timeline

200,000 BC – The Precursor Empire thrives in the Galaxy as the only known intelligent species they know of. Their empire spans the Galaxy and they begin artificially creating species to eventually join them on the Galactic stage.

190,000 BC – The Precursor's have Created the Forerunner and Human Species out of their own likeness. Each containing their qualities in different ways, to see which is more successful. They become capable of Trans-Galactic Travel, But do not attempt it in fear of Discovering a Civilisation similar to themselves or even more advanced.

170,000 BC – The Precursor's see the potential in Humanity and schedule the Forerunners for extermination. The Forerunner's discover the Precursor's and their plans. They pre-emptively strike and start the Precursor-Forerunner War.

165,000 BC – The Forerunners, afraid of extinction at the Precursor's hands, resort to bio-engineered viruses and ruthless tactics. The war is turning in their favour. The Precursor's, believing themselves above such measures continue the war as they always have.

160,000 BC – The Precursor Empire is smashed, The Forerunner's victorious begin the extinction of the Precursor species. The Remnants of the Precursor Military and Scientists create the Flood and leave it dormant in systems for the Forerunner to discover. The Precursors prepare to leave the Galaxy heading for the Andromeda Galaxy with as much of their Civilisation as possible. The Reapers strike, preventing the Precursors from surviving and possibly returning. They ensure they are not discovered by the Forerunners.

150,000 BC – All traces of the Forerunner-Precursor war are erased from records. The Forerunner Ecumene not wanting future generations to know of the atrocities they committed.

The Reapers are calculating in hibernation at this time. Preparing for the right time to strike against the Forerunners and continue their cycle.

110,000 BC – The Forerunner-Human War begins and Ends in this time. The Forerunners defeating Humanities smaller Empire and de-evolving them to a Tier 7 species and leaving them on their home-world to restart their civilisation.

During this time though, the Extra-Galactic parasite had entered the Galaxy and begun infecting Human Worlds. The Human Empire, wanting more worlds to survive on, invade Forerunner territory starting the War. The Humans fighting a war on 2 separate fronts, find a 'Cure' for the Flood and defeat it. Their Military exhausted, they fall to the Forerunner's and they destroy the cure for the Flood Parasite, their last vengeance against the Forerunner's.

Unbeknownst to everyone, the Flood was discovered by indoctrinated agents and released by them, said agents were also responsible for the start of the Forerunner-Human War.

100,000 BC – The Reapers use indoctrinated agents again to locate the flood. They use the flood to begin the Forerunner-Flood War. The war lasted for 300 years. The Forerunners losing rapidly to the all consuming parasite. Agents that are indoctrinated aid the flood in weakening the Forerunner defences and strategies.

The Forerunner's in secret develop the Halo Array and the Ark. They catalogue as many species as they can before firing the array and leaving the Galaxy life-less, sacrificing themselves in the process. The Reapers, surprised at the outcome of the War, calculate how long it will take for life to re-emerge. They discover the Forerunner Ships restoring life to the Galaxy, they let them full fill their purpose before eradicating the remnants of the Forerunner Ecumene. They enter hibernation after rebuilding the slightly damaged Mass Relay Network and Citadel after the Forerunner-Flood War.

52,000 BC – The Prothean Empire leaves its home system via Mass Effect Technology ( The newly implemented trap by the Reapers, if the Civilisations are based on Mass effect technology they will advance down a lesser path. Which will make them pose less of a threat. )

The Prothean Empire reaches its height as it controls most of the Galaxy and the Citadel. The other space-faring species that inhabit the Galaxy have the same technology as the Protheans, but are not as wide spread or large as them.

51,000 BC – The Prothean Empire discovers the Zha'til and realizes the threat posed by machine intelligence. The Protheans begin to wage war against them to defend themselves, the Zha'til are relentless. The Protheans begin calculating their chances of Victory.

The Protheans calculate they will lose. Military leaders assume control of the Government and 'Assimilate' the other species of the Galaxy to unite against the Hostile AI's. The war rages on devastating many worlds and crippling the Galactic Economy. The Prothean Empire pushes the Zha'til back to their home system and cause a premature stellar collapse, destroying the Zha'til entirely. The rebuilding of the Galaxy is a slow process.

50,000 BC – The Prothean Empire begins 'Guiding' primitive species to become ready to 'join' the Empire when they become Space-Faring. The Reapers Attack through the Citadel, destroying the Galactic Government and taking control over the Mass-Relay system. The Protheans stop all 'Guiding' projects to prevent them from being targeted by the Reapers. The Protheans wage an war to prevent the Inevitable Extinction they face. The Protheans are defeated and the Reapers retreat through the Citadel to allow the Cycle to continue.

A team of Prothean scientists survived the war in stasis pods on Ilos. They use the Conduit to travel to the Citadel and they prevent the Citadel from being able to open as a mass relay to dark space. They die completing their goal and the keepers remove any trace of their existence from the Station.

1000 BC – The Krogan Civilisation begins a long cold war between each of its individual Nations. Each trying to out do the other. They prevent Nuclear catastrophe as they realise they would crumble their society to cavemen once again. However, a genetically engineered virus intended to prevent rival nations from out reproducing their own escapes containment. It infects the entire Krogan Population and reduces their birthrate from 1000 eggs per clutch to just 50. it become so ingrained into Krogan DNA that it is incapable of being removed.

The Release of the Virus taught the Krogan what they could do if they were pit against each other. They set aside their differences and form the Krogan Empire.

Because Nuclear war was averted, The Krogan population is not all succumb to blood rage. The few who are become submitted to special programs to help themselves to overcome it.

500 BC – The Asari Discover the Citadel and make it their head of Government. They expand into more territory. The Krogan become a space-faring race and open their mass relay.

450 BC – The Salarians discover the Citadel and the Asari. They together form the Citadel Council to oversee the Galaxy. The Council time line is formed at 0 GST

400 BC – The Council discovers the Volus and with their help create the Galaxy wide Banking act. Establishing the Credit as standard Currency. The Volus become the first associate-member species of the Council.

350 BC – The Elcor join the Galactic Community as they are discovered by the Asari. They become the 2nd Associate-Member species of the Council.

300 BC – Council space expands. A Salarian research vessel opens a Relay to Rachni Space. The Rachni Wars begin with the Rachni declaring war on the Council species. The War becomes one-sided with the Rachni overpowering the Council.

250 BC – The Salarians Discover the Krogan Empire and negotiations begin between the Council and the Krogan Empire. The Krogan agree to help the Council in the war against the Rachni, realising they too will be threatened. They become the 3rd Associate-Member species of the Council. The Krogan agree to it because the Council will provide them with more effective technology in the War. The Krogan become the front-line force of the Citadel.

235 BC – The Quarians make contact with the Council and join the Galactic community, becoming the 4th associate-member species. A law forbidding the opening of dormant mass relays is instituted.

The Krogan discover the Turian Hierarchy trying to open a mass relay and open fire to prevent them. Starting a brief war between them. The Council intervened forcing a truce and apologized to the Hierarchy explaining their predicament. The Turian Hierarchy join Citadel as the 5th associate-member species.

200 BC – The Rachni are declared extinct as the Council took the fight to the Rachni home world and destroyed them. The recovery of Council Space begins.

100 BC – The Turian and Krogan are made Council members in respect to their instrumental efforts against the Rachni. The Treaty of Farixen is signed, restricting the amount of ships each species has.

The Turian and Krogan become the main peace-keeping force of the Council, while the Salarians become the intelligence experts and the Asari are the most influential species in the Galaxy. The ratio of Dreadnoughts from Council Member species to Associate-Member species follows 5:1.

100 AD – The Batarians join the Galactic community as the 6th associate member species. The Council warn them of their anti-slavery laws. Nevertheless they remain a slavery involved society and expand.

2160 AD – The Human race unites under the UNSC and ends the Interplanetary war in their solar system.

The Quarian made Geth rebel and the Morning war begins.

2180 – Humanity creates the Slip-space drive in order to expand outside of its solar system. The colonization era begins.

2300 – The UNSC territory consists of over 500 worlds, all tightly nit into the Home Cluster of Humanity. Expansion shows no signs of stopping.

The Quarians are defeated by the Geth and request aid form the Council. They refuse and banish the Quarians from the Citadel for their foolish actions.

2500 – The UNSC and Sangheili Empire meet. They open diplomatic relations when a UNSC vessel exits slipspace in a Sangheili controlled system. They learn a great deal about each other and both governments collaborate.

The Sangheili are discovered to have similar technology to the UNSC, however they have different Military tactics. The UNSC's Military is more effective overall but the Sangheili have more Ships In their Navy.

2525 – The Spartan Project reaches fruition. Producing the most effective fighting force known to either side.

Rather than begin war with each other, they decide to form the Systems Alliance. Both races under one Government. They both understand that Unity would be preferable to War. They begin sharing many technologies with each other and expand their territory. The Spartan Project is kept a solely Human project.

2550 – The Systems Alliance discovers Installation 04. they accidentally release the Flood from containment and destroy the ring but not before learning of the Location of the Ark.

An expedition to the Ark is planned. The Journey will be long.

The Systems Alliance arrives at the Ark to find it beginning construction of the Halo Ring. They learn that all Forerunner technology responds to Humans as they are the Rightful Reclaimers of the Forerunners. Shocked by this revelation they begin making the Ark the Capital of their Government.

ODP's are planned for construction. Alongside many other plans.

The Lekgolo are discovered. They have a few planets in separate systems under their control. They are invited to Join the Systems Alliance.

2560 – The Huragok are found in many Forerunner Installations. They respond to Human presence well and are incorporated into the Systems Alliance.

2568 – The Unggoy race are discovered, struggling to survive on their polluted planet. The Systems Alliance aids them on the condition they join the Systems Alliance. They agree and the Alliance helps them locate 3 other planets for them to inhabit.

The Unggoy begin filling roles as engineers and even Military when given proper training and equipment.

2571 – After a lot of hard work thanks to Alliance Scientists, they create their first energy projector weaponry. Thanks to ingenuity from the Sangheili, Humans and Lekgolo they create the Type 47 – Ultra Heavy Assault Platform or as it is commonly called the Scarab. It is capable of being dropped from orbit alongside ODST's. Energy projector infantry weapons see limited use, mainly from Sangheili and Lekgolo Forces, Humans being reluctant to change from the tried and true method of ballistic weaponry. Nevertheless Scarab's are scheduled for mass production into the Alliance Military and ships undergo slight modifications to be capable of launching Scarab's from orbit.

2575 – The Systems Alliance discovers a Mass-Relay at one of its border colonies. It sends a nearby Cruiser to investigate and activate the Artefact once they determine its purpose.

Scientists aboard the Ark discover the History of the Forerunners and the Capability of the Flood. They also learn of the Ancient Human Empire and the other species saved by the Forerunners but keep most of the History secret to the Public.

Many cities are constructed on the Ark.

A survey is conducted to determine the extent of the Systems Alliance

Home planets : 3 (Human, Sangheili and Lekgolo)

Colonies : 876 ( Shared between species)

Naval Capacity : 2000 Frigates, 2000 Destroyers, 1000 Cruisers, 50 Carriers and 1 Dreadnought.

A similar survey is conducted by the Council.

Home Planets : 7

Colonies of Council Member Species : 854 (Altogether)

Colonies of Associate Member Species : 385

Naval Capacity : 6500 Frigates, 4000 Cruisers and 1000 Dreadnoughts.

Codex

The Systems Alliance – The Systems Alliance was formed from Humans and Sangheili to ensure they could live in peace against outside threats and to avert war between them. They inducted the Lekgolo into their Government also. The Lekgolo are the strangest of the species but are nonetheless treated as any sapient when they have formed themselves into a Mgalekgolo. The Systems Alliance welcomes any and all peaceful species but will wage war against those who come to do harm.

The Human and Sangheili Races are the Founding members of the Alliance. Therefore are unable to be removed from the Alliance due to their roles. The Lekgolo and Unggoy share the same privileges as the other 2 races, but are able to be removed from the Alliance should their actions warrant such removal.

Their Technology is different from the Citadel Races as they are not dependant on Element Zero technology and therefore do not use Mass-Relays (Therefore sidestepping the Reaper Trap). They are having a hard time understanding the Forerunner Technology but are putting in Large amounts of time and effort into learning more. (They basically have technology more advanced than the UNSC's tech from Halo, but are not as advanced as the Covenant)

They have incorporated Shielding technology to their Armed Forces and Naval Forces.

No Forerunner Technology was found until they discovered Installation 04.

The Citadel Council – The Council consists of the Asari as Mediators and Centrists, the Salarians as Intelligence Gatherers, the Krogan and Turian races as the Bulk of the Council Militaries. Their technology is based upon Mass Effect Technology. They depend on Element Zero to sustain their Civilisations and also have a Large Military.

They base much of their technology upon the Prothean ruins they come across and have not yet discovered a Forerunner structure yet.

Their Kinetic Barrier technology is very good at stopping projectile weaponry but in theory would be unable to prevent a shot from a directed energy weapon.

The Citadel – The Citadel Is a massive Space station that resembles a pentagram. Its central ring has a diameter of 7.2 kilometres, from which 5 arms protrude. These arms measure 43.6 kilometres long and 330 metres thick. It is capable of closing the arms to make it impenetrable. It is presumed to have been constructed by the Protheans who vanished in a Galactic extinction event over 50,000 years ago, they are also believed to have constructed the Mass Relays.

The Ark – The Ark is a Space station that resides out of the Border of the Milky Way Galaxy. It measures at 127,530 kilometres in Length and 5000 Kilometres in height. It presumed to have been the Seat of Government for the long dead race the Forerunners. The Ring worlds it creates are thought to be fortress worlds for the Forerunners. It is not public knowledge what it was built for and what those ring worlds contain. It houses millions of Sentinels that run and maintain the Ark ensuring it runs carefully.

Hello again :) before you ask, I don't even understand my own randomness for posting this separate story. Maybe I enjoy alternate first contact scenarios who knows?

Either way I decided to give the Krogan a new look in my story. If any of you know the story to them then you will know that the Krogan's blood rage is a genetic defect or something like that. It was uncommon before they nuked themselves then afterwards only the people who had it were capable of surviving the harshness of Tuchanka. I decided to make them more presentable. They may be warlike but I always wondered what would happen had they not rebelled.

I also changed some things around. Most of the covenant species are not in existence in this fic, if you don't like it them read another story. Simple as.

Any who, let me know what you think in the review :D I may also add bits to the first time-line section when I read it again.