My opinion on the matter is the traveller is a force of change, neither good nor bad. However as it moved through the universe, interested parties began hunting the traveler for their own means. Example being the fallen wanting to use the "great machine" to raise their culture back to the glory it once was or the cabal wanting to use it as a weapon against the darkness. I believe that the darkness is something that doesn't want other species to change because their rapid evolution and advancement in technology is a threat to its power and position in the universe. On a lesser note i also believe there are multiple travelers in our universe and the beings who made them are now extinct.