Much like barbarian camps in Total War: Attila, they harbor all of the planetary improvements and can easily transport them from system to system. Meanwhile, the Vodyani, who religiously worship the Virtual Endless, don't colonize planets as much as subjugate systems with their Arks. If that ship remains undisturbed for 10 turns, you can immediately colonize the system, which makes the spread of the Unfallen very slow and methodical. Inquisitive and dedicated, the Endless were able to make great advances in the fields of science, which culminated in them achieving virtualization, allowing them to upload their minds into machines and giving them eternal life. At the beginning, every system can have only one route. The only term is have a peace with at least one faction and research proper technology: then the trade routes activate automatically. Instead, they send a ship to neighboring system to plant a beacon for interstellar vines. Endless Space 2 is set in the universe that was long ago dominated by a powerful race called the Endless. Luxury resources can be traded with other races. Unfallen, ents in space, don't have colonizer vessels.
United Empire, a hegemony both corporate and feudal, can have the Emperor flex his muscle and hasten not only build times, but even research by spending the influence resource, making UE the race most interested in its generation. Unless they don't: while all races have their own quirks and gameplay differences, some are more different than others.