Gameplay:

Affinity:

-Orbital Power Channeling: Ships receive a large bonus to both offense and defense (30%-80%) when in a system of their own. They also receive a large penalty (30%-50%) when in a system that's not controlled by them. As such they will find it much easier to defend their own territory while finding it nigh impossible to wage war on others

Traits:

-Tolerance (Hot): Capable of colonizing hot planets early on as they originate from an Ash planet

-Patience and Adaption: Influence costs gradually increase as the faction expands/researches/comes into contact with others

-Cooperation:  bonuses to them and allies for positive treaties

-Slow population growth: To prevent players from picking this faction, going full expansion early on, and then relying on the superior defense to lock others out their population growth should probably be lowered a bit

Race specific techs:

-Stealth (Era 2/3): Allows the faction to build stealth modules into their ship to make up for the weakness outside of their systems. This module should have to be slotted instead of a weapon, making it's main purpose exploration and staying informed on galactic affairs

-Affinity Penalty Reduction (Era 4/5): Allows them to reduce the penalty outside of their systems in the very late game to prevent potential stalemates

Victory: Diplomatic/Wonder(Industry)

How they'd be played: Explore the universe and cooperate to achieve diplomatic victory. If that fails, hold on tight to your part of the galaxy and achieve victory through

One of my ideas is to create a faction and a gameplay that pushes the player towards diplomacy, without imposing penalties from negative treaties with other factions like wars. This is to avoid them being useless in multiplayer as treaty penalties would allow a couple of players to cripple them just by declaring war. That being said, the traits above are ideas and some probably should be weeded out or adapted.

(There's no definite name yet. Xaithe or Ytreilva came to mind, but I don't mind something else either.)

Biography:

They came to be as a race of machines, made to serve their creators, and as with many machines, eventually developed sentience. The population had very divergent reactions to this, some trying to work things out, some fearing them, leading to a multitude of cultural problems. With time the machines have been deemed too dangerous and the xenophobes won the battle of opinions, starting a global war that ended in a nuclear winter, the extinction of their creators and almost the extinction of the machines too. They began to adapt to their new world, covered in ashes, and had a lot of time to think, but since their reproductive and self-advancing abilities were limited they physically stayed mostly the same for countless centuries/millennia, with only mental evolution progressing.

Recently a cosmic wave of  reached their planet, and with it came the ability to finally evolve in earnest. Dedicated to explore the universe, learn its secrets and to defend their home and lives, but with little interest in being drawn into any war ever again, they set their sights to the stars, hoping for nicer faces than those that brought them into being.

I think the offense bonuse in your territory is too much, this faction seems unassailable with such an defense army. The bonus in defense is enouthg I think ... Otherwise it is a great faction, and the gameplay fits well with the background.