I had an idea, some time ago, for a book acctualy, sad that I never wrote that book.
So, the idea is that an ancient race had a massive religous book, but it was forgotten under the actions of time, except for a cult, the cult of the lost god.
So, a certain day, a cientist craft a hypercomputer so it can simulate the most varied thing in nature, cells, moleculles, scentient life, etc. But that hypercomputer had one single flaw: After every single simulation, it sould be shut down, or it would likely assimulate to the simulation, and would become useless
And there it is the start of the faction, a scientis, that works with that same cult gets tho the computer and makes it simulate the mind of the lost god, based on its descriptions on the book, the simullation is an absolute sucess, but the scientist does not want to shut down the machine, so it assimilates to the entity, and the god entity just see sin into that society, and exterminates it all, and starts creating the robotic clones, from the images of """angels""" and seeks to ""purify"" the galaxy, by bringing every life to the light (his consciouness)

it would be a very military focused faction, indeed, but diplomacy existis for those who bend towards the light.