-no Approval penalty from overpopulation

-All diplomatic/trade actions taken offer the other faction a boost to approval

-When a faction declares war the approval granted is lost.

-Diplomacy options are available from the start and do not need to be researched.

-The Accretion are meant to integrate themselves into other factions approval strategies early on so that they become a vital part of their empire management, such that were they to declare war on the Accretion and lose their approval support they would be severely crippled.

A conglomerate civilization united under a singular goal to spread an ancient Fungal life form across the stars. Its unknown whether the Fungus is sentient but it connects the people of the Accretion telepathically and all worship it as a god-king. The Holy Accretion is best suited for warm humid climates. The Accretion is largely peaceful, they do not compel acceptance into the order, but offer to other civilizations the benefits of becoming One.  The Accretion looks like every other organic species but is marked by a milky hue to the eyes and an Axlotl like fungal growth at the neck that allows the symbiotic fungus to breathe.

I like the concept of a fungal based faction (that is creepy and mind-controlly), rather than the typical humanoid ones. It makes the world feel more diverse. So good idea!

From the traits, other factions have incentives to make peace with the accretion, but they themselves do not have a reason to make peace. In fact a player may instead prefer to not form alliances because they don't want to give them the Accretion's bonuses. I try to balance this gameplay in my own submission. Maybe you can do something similar and/or better, that fits into the cool lore you've established?