0 AFSF (After First Space Flight)

By some miracle of coincidence, Humans and Forerunners manage to achieve space flight on the exact same day, almost down to the hour. Their methods, however, are vastly different. Humans literally launched a pod (with a human inside) from a massive railgun. Forerunners, not being as suicidal as humans, launch a chemically propelled rocket.

7 AFSF

Humans land on their moon, and set up an interplanetary rail gun. The pods launched by the rail gun use a combination of chemical propellants and ion engines to slow down in Earth's atmosphere. The railgun is set up on a massive railway that spans the diameter of the moon, so the railgun is constantly pointing at Earth.

8 AFSF

Forerunners set up their own base on their moon. Forerunners have switched to a type of hydrogen fuel that constantly burns, unique to their planet. Using heat converters, a nearly infinite energy source is discovered.

10 AFSF

Forerunners notice the massive flashes of light that coincide with the moon's rail gun firing. They quickly deduct that intelligent alien life must be in the neighbouring system (then called the Contarnium system.) They attempt to communicate in any way possible. Combinations of radio signals, visual lights, and an attempt to imitate the flash of a rail gun all fail. Finally, the Forerunners literally lob a satellite at the humans. That got their attention.

29 AFSF

Satellite arrives in Sol system. After humanity retrieves the satellite, peaceful images of Forerunner society are found. Scientists are shocked at the similarities between human and forerunner anatomy. They send a satellite back, filled with similar images, as well as a simple pictographic message of peace. A visual dictionary, with words connected with images are sent.

Forerunners create first AIs.

36 AFSF

The Human satellite is considerably faster, arriving in the Forerunner system after only 7 years. Forerunner AIs pour over the visual dictionary, creating a simple translator.

A massive key-like object is found in the SOL system. Studying it shows there was a massive hole where the power core was presumed to be.

39 AFSF

Another message from the humans is received- meeting in a location about halfway between Sol and Alpha Centauri. AIs developed independently by humans. Full citizen rights are given to AIs on both sides.

41 AFSF

Travel technology on both sides have been vastly improved. The meeting commenced. The humans are surprised by the translator tech, which is shared freely by the Forerunners. The Forerunners are surprisingly open about their technology, prompting Humanity to give them blueprints to an old railgun design. A mutual alliance is made.

68 AFSF

Joint science and civilian projects are common. A massive space station is built at the halfway point between Alpha Centauri and Sol. Those willing to suffer the (now) 2 month journey are usually scientists and military men, doing joint exercises. Most technology merges, with applied tech from both sides working their way to civilian life. A joint team works on creating "slipspace drives", which, in theory, could move at hundreds of light years per second.

87 AFSF

Slipstream drive is tested. It made the jump from Forerunner to Human space in exactly 0.089 seconds. Forerunners and Humans migrate to their counterpart's worlds. The races grow closer. A joint military is created, as well as joint colonisation efforts.

92 AFSF

6 neighboring systems colonised simultaneously. This stretches the joint navy to the absolute limit. As a result, orbital defence platforms are created, as a stopgap measure until the proper ships can arrive. These grow immensely popular, and funds are allocated to the development of more advanced ODPs.

96 AFSF

The alliance is named: The Republic of Interdependent Species(RIS). First Dreadnought is created, at a massive 5 km long, it's an impressive display of power projection. 32nd world is joint colonised.

157 AFSF

First contact with Citadel races.

In Citadel Navy Vessel: Manae's Flight.

Captain Decius Flavius, of the Turian Hierarchy, was pissed. Stuck on a ship, where nothing happened, in a patrol fleet, where nothing happened, patrolling a border, where nothing happened.

"QEC, status update?"

"Nothing to report, captain."

"Sensors?"

"Nothing here, sir"

"General status update?"

"All systems nominal, captain"

"Well, surprise surprise", the captain thought.

"Join the navy, they said. Explore the galaxy, they said. You could become a hero, they sai-"

That was the last thing that ran through the captain's mind, before a massive wormhole appeared off the port side of his ship, and a massive, 12 km, vessel plowed through his little frigate, cutting it in half.

On board Republic of Interdependent Species Cruiser, Peace Through Sacrifice.

Captain Thomas Lasky slumped on the bridge of the Peace Through Sacrifice, staring into the vastness of Slipspace. The timer on the top right of the main screen slowly ticked down the time to the destination. As it reached zero, there was the usual thud of returning to real-space, and then another sound that wasn't normal- a massive boom, as well as the sound of metal tearing.

"Captain. Minor impact across the bow. Minimal damage to shields, no damage to the ship itself."

The ship's AI, Caitlin, reported.

"Appeared to be a small asteroid, or- oh, shit"

"Caitlin? Something wrong?" The captain asked.

"There appear to be 32 vessels of unidentified origin and design directly in front of our bow. Scans show the unidentified ships to be of the same material as the debris from the object we hit. I… think we might have cut one of their ships in half."

Silence fell on the bridge. The Forerunner com officer, Tranquility of Fortitude, summed it up pretty accurately in two words-

"Well, shit."

Aboard Turian Hierarchy flagship Palaven's Might

"Sir! Massive anomaly, port side!"

"Spirits! Something's coming through! It's massive!"

"VI reports height of… 1 kilometre! Length is 9 kilometres, and growing!

Admiral Arthcontus Revolutus listened as the horrifying reports swept in. The Manae's Flight had been completely obliterated by the unknown Dreadnought, with seemingly no damage done to the alien vessel.

"All ships, prepare firing solutions. Battle stations, prepare to engage!"

Republic of Interdependent Species cruiser, Peace Through Sacrifice.

"Sir, alien vessel has prepared firing vectors, and are about to engage"

Lasky ran his hand through his hair.

"Of all the infinite space in the universe, I just had to land on top of that one ship, didn't I? Come in a kilometre to the left? Noo… I just had to smash that one alien… frigate? Too small to be military, must be a civilian convoy."

"Sir?"

Caitlin's soft voice brought him back to the present.

"Hail them. Any way you could have a translator within the next 5 seconds?"

"Already hacked in, and got a copy of their language" Caitlin nonchalantly stated.

"Wait, what? I was joking!"

"I wasn't."

"Er… Captain? Sorry to interrupt, but they've accepted our hail."

"On screen."

And then it appeared on the screen...