NPC Faction question

[Arcylis]

Are all NPC factions opposed to each other? This would mean that a player can only ally themselves with one NPC faction without additional effort. Is this the case?

Has anyone discovered nice synergies between NPC factions that would make it worth it to build relations with 2 or 3 factions at once?

Does conquering an NPC faction have any benefits beyond the level 5 sector? Can you get their units or mods by chance after conquering them?

 

[Ericridge]

I got really annoyed with demands from NPCS and their whines. In current game I decided to just ally with Autonom and tell everyone to fuck off. Of course this results in me fighting a war against spacers/psifish. They're crying pretty hard now though and demanding a sector of mine if I want peace with them. But autonom is pretty happy with me and once in a while they beg for a tribute from me. /shrug

 

[Promethian]

You can ally two of them at once. Quests give 10 rep and only take 5 from the other. I find it worthwhile to do two because the quests give good value. Kill that stack, get unit xp and bonus resources. Gladly. More happy factions also gives you bonus influence per turn and gets your overall rep up which reduces the cost of the shops.

Extra bonuses if you are Syndicate and/or Celestian.

Noble Diplomats gets you 15 energy per turn for every level of positive rep with an NPC faction for every faction. So if you have friendly with Growth and peace with Spacers that is 35 energy per turn. It also gets you 1 influence per turn on the same paradigm. Its a ton of energy early in the game and stays relevant for a long time.

Celestian has a doctrine that reduces the turn cooldown on the quests by 1 (5 to 4). Its a nice resources bump overall. Especially if you run The Emmisary as well to double the influence income from quests. Celestian also has a covert op that reduces a target's rep with a faction by 20 and increases your own by the same amount. This can make it possible to get friendly with every NPC faction AND make them fight with all your enemies. Celestians play the NPC game better than anybody by a long shot.

 

[Jean-Luc]

You can ally two of them at once. Quests give 10 rep and only take 5 from the other.

This is true. Also the Unification Efforts doctrine provides a 50% bonus to relations gain from quests so you can speed up progress with two NPCs or even gradually befriend all 3 though it'd be a slow process.