Timeline

We going to use Mass effect times so BCE and CE

2,500,000,000 BCE:

Greater humanity begins colonization of mars. Project O.M.A.M.C become public knowledge to the citizens of earth and mars.

Elves begin colonization of their first colony.

Dwarves begin colonization of their first colony.

They become the precursors to all other races.

2,499,500,000 BCE:

First contact between the precursors.

In 500,000 years each precursors have grown in massive technological power and military might with each planet they claim.

They redraw territory and designated a lot of empty systems to seed new life, Project Vibrancy begins.

2,499,000,000 BCE:

The precursors have grown to unfathomable heights. They are seeing the fruits of Progect Vibrancy grow and begin creating it's own life.

2,397,000,000 BCE:

First contact with a new species end in the death of the entire race.

The precursors think nothing of it and send send envoys to multiple other new sapient species.

It ends in the death of all of them they enter isolation to create races in there image so they can interact with the new races.

2,395,000,000 BCE:

The lesser races of each Precursors is created and introduced on a galactic scale.

The galaxy celebrates they can talk to the precursors.

2,256,000,000 BCE:

The precursors begging to heavily militarize there worlds and forces, but also begin helping other races grow in strength.

When asked why the only response received is "Prepare yourselves for you will know when the time comes".

2,250,000,000 BCE:

The arrival, unknown beings from outside the universe arrive slaughtering the the outer edge of the galaxy. Hitting a wall when precursors fleets engage them.

The surviving races fight back with ferocity pushing them back but its an ocean cannot fully be stoped.

Worlds and space becomes contaminated the precursors have turned the ocean to a stream of eldrich horrors attacking the races.

2,200,000,000 BCE:

The races fought back but couldn't stop the eldrich horrors from purging the galaxy.

The precursors fought back the horrors and banished them from the universe still countless hide in the universe.

As they set off to purge the universe of horrors there economy is collapsing and worlds dying.

2,050,000,000 BCE:

The universe was purged not a trace of sentient or non sentient life remained just dead rocks in space.

The precursors returned to there home devoid of life reminding them of there failure to protect all those new races.

2,025,000,000 BCE:

After countless years of meeting and rebuilding there homeworld to there original biomes they came to an agreement. All precursors are to enter stasis in 25million years and O.M.A.M.C will awaken them in the future.

2,000,000,000 BCE:

After 25 million years of preparation everyone is ready.

The core precursors worlds have been moved and clocked in extra galactic space.

As they enter stasis Project Vibrancy is restarted on a universal scale. Expected completion 5 million years.

1,995,000,000 BCE:

Project Vibrancy is complete the universe has been seeded with life.

1,984,000,000 BCE:

O.M.A.M.C has a critical failure and begins to repair the damage.

2 years pass and damage is repaired.

5 years pass and O.M.A.M.C officially dies leaving a false message for the original mind he was created from and a false history for it.

1,900,000,000 BCE:

Element zero begins growing in the galaxy from the eldrich corpses that had tainted asteroids and space dust.

Ezzo causes havoc on the background of the universe beginning it's slow collapse and destruction giving an infinite a finite life.

Planets fall out of there projected paths and entire star clusters die spreading the ezzo across the milkyway.

1,500,000,000 BCE:

Leviathans achieve interstellar travel.

This is where mass effect timelines begins.

Yes I know mass effect timeline has no beginning but screw you my story I say they been around for 1.5 billion years.

===============================

But honestly I'd like your general thoughts it will be edited and updated is things and times feel wrong but up to you guys if you want things added or removed let me know.

Been considering a discord but not fully drawn to the idea unless you want it?