There are spoiler boxes for that very reason, so that people who don't want to see spoilers won't have to. I want to see what it is. In the product description for Distant worlds Legends, it lists a "Hidden Faction" so there must be a hidden faction unless the company is lying about it. So I saw no need to ask if there is a hidden faction when it is explicitly listed as such. I have been trying to find it but haven't yet after many hours so I am getting frustrated.
This is what it says under features for Distant worlds: Legends:
•New character system, including Leaders, Admirals, Generals, Ambassadors, Governors, Agents and Scientists, all with defined skills and traits and the opportunity to advance and improve
•New modelling of borders and spheres of influence
•New expanded gameplay with race-specific events and victory conditions, as well as a new hidden faction!
•Expanded technology tree, including dedicated carriers, cutting lasers, rail guns, new planetary facilities and wonders
•Improved AI and an updated Diplomacy system with refuelling and mining rights as well as immigration policies
•Improved fleet management and automation, including fleet postures
•Improved modding support, including full race and character modding