Names
Dr. Richard Langstrom, Duke Greenhaven: more or less creator of the AI. Worked with Marcus Artain. Husband of Dorothy Langstrom. Latter allied with the Spire Empire.
Dr. Dorothy V. Langstrom: Wife of Richard. One of the main figure of the Fallen Spire campaign. Also appear in the Showdown and Exodian campaigns.
Dr. Marcus Artain: Collaborated with Richard Langstrom on the creation of the AI. Evoked in the Showdown and Exodian campaigns.
AI: ancient Spire artifact/being. Also called the Core.
The Exodian Blade: "sibling" of the AI/Core. Also ancient Spire artifact/being.
Entelemaren Exaron the Seventh: Spire Emperor. One of the main figure of the Fallen Spire campaign.
NGC 224: code name of another galaxy, where the Spire homeworld and the Core (and its production facilities) are.
Chronological Order
Two "Exodian", also called "Exile" were both banished by ancient Spire, from the galaxy NGC 224, through the "Pyletzan Conduit" (one of hte exogalactic wormholes) and to the Milky Way, "thousands of years ago", and their ability to "walk among the stars" was taken from them. They defended their ancient Emperor (Probably Entelemaren Exaron the Seventh) but were falsely accused of treason.
Meanwhile (maybe), on Earth, a civil war waged during 800 years during which several AI were developed, however they are nothing compared to the AI from AI War. The robot army in Bionic Dues might be of these AIs at the begining of the civil war (if it's true, we could deduce that Bionic Dues is at least 800 years before AI War). On the other hand, Release Raptor seems to be during the civil war; when exactly, I can't tell right now.
After the civil war, one Exodian was found and studied by Richard Langstrom and Artain. They built a machine around it, supposedly a sort of AI, developed during/after the civil war. That Exodian/Human machine was called "the Core", or "AI". It tricked Langstrom and Artain (a bit more complex, but yet), destroyed Earth, traversed back the Pyletzan Conduit and fought the Spire empire in galaxy NGC 224. Richard Langstrom followed it and supposedly joined the Spire homeworld and met Enteleramen Exaron, the emperor.
Artain seems to have tried to connect the four Showdown Devices in order to disrupt the AI warp grid in the Milky Way, but the Core found it and attacked. "We're not picking up debris of the doctor's ship, so it seems they at least made it into deep space."
The Core attacked the Spire homeworld in NGC 224 and destroyed the main exo-galactic transit gate. The Emperor's flagship was caught in the rift provoked by this destruction and crached into the Milky Way; The Emperor was rescued by the players. The remainder of the Imperial fleet hold the AI Core and defend the Spire homeworld.
If the players build a Spire army in the Milky Way and destroy the two AI's command facilities, the Imperial fleet would be able to attack and destroy the Core.
The players can also build an exo-galactic transreceiver (with the core of the Emperor's starship) to restore the exo-galactic transit network, join the other Spire fleets in neighboring galaxies and defeat the AI in both NGC 224 and the Milky Way.
Endings
In the vanilla game, players destroy two sub-AIs and cut the main AI, the Core, from the Murdock quadrant and the Milky Way.
In the Fallen Spire campaign, players find Exaron the Seventh, establish a link between the galaxies. Then other Spire armies in neighbouring galaxies come to save both the Spire homeworld in NGC 224 and the players in the Milky Way, destroying the two sub-AIs and, presumably, the Core.
In the Shadow campaign, players find a Shadow Spire artifact and heal Earth after the AI was cut from the Milky Way.
In the Exodian Blade campaign, players find the AI's "sibling" and repair it, then it goes to the other galaxy and stop its sibling (the AI), presumably sacrificing itself.
Suppositions
The Exodians' ability to communicate at long distance (supposedly using quantum entangling) made galactic army control possible, hence the central command AI and possibly player's "RTS" ability. That Exodians' ability might be the same base technology for the Pyletzan Conduit (exo wormholes) and the Spire trans-galactic transit network. Is the AI's warp grid, which causes interferences with the Spire cities, of a similar kind?
There was a war between Spire and Zenith long ago. We can suppose the broken golems were destroyed by a Spire army. Provided the Zenith are only remnants and the Spire is present in at least several galaxies, we can conjecture the Spire won this very old war.
Other Minor Characters
Gustav van Eik: main character from the splinter faction "Epsilon Eridani".
Vice Admiral Putnam: main character from the splinter faction "In Memoriam Terra".
Dr. Michael Davidson, Space Telemetry Lab: rapporter for the Fallen Spire and Exodian Blade campaign.
List of splinter factions
(+ is friendly, - is aggressive, ? is both or unknown or neutral)
Spire
+ Spire Empire (homeworld in NGC 224, Imperial armada, Emperor Entelemaren Exaron the Seventh, Fallen Spire campaign, etc; NOT IN NEBULAE)
- Dark Spire (Vengence Generator, but also Nebulae)
? Shadow Spire (Champion technology and Planetary Adjustment device)
+ Gray Spire ("This particular group was a regular trading partner for several human factions before the AI war")
Human
+ Resistence (Resistence Fighters MF & Colony Rebellion MF; NOT IN NEBULAE)
+ Epsilon Eridani Remnant ("Epsilon Eridani Mining Consortium")
- Sorrow's Fang (== MF's Marauders? not same ships, however)
+ In Memoriam Terra
Neinzul
- Astrid (said to be old Neinzul/AI hybrids)
+ Mourner Wardens
? Roaming Clans (Roaming Enclaves MF and also briefly in Nebulae)
- Preservation Wardens (NOT IN NEBULAE)
Zenith
+ Shattered Pillar ("refugees")
+ Dyson Sphere (MF and also "been hacked" gatlings in Nebulae)
- Citadel Ascendant = Zenith Architect (hacked Dyson Gatlings; converted colony ships; enemies to the Shattered Pillar)
+ Ravenous Shadow (Lone big Zenith being? Like the Devourer golem?)
- Miner Golems (NOT IN NEBULAE)