So I'm starting to theorize here guys! Well start by saying we can confirm that the traveler moves from location to location. We know based on the grimiore that when the traveler came we entered the golden age and after that we fell into the dark age. Now we fight to protect what remains of the traveller with our lives. Let's apply this to our "enemies of the darkness". Fallen: Obviously they have advanced technological skills. Demonstrated by scorch cannons and the S.A.B.E.R. (For example) that they are making these complex machines from scrap. This leads me to believe that they went through a golden age of sorts as well. Perhaps the traveller was with them once too. Assuming it once was it obviously left probably sending them hurdling into a dark age. With that plunder into chaos the fallen became segregated forming the different houses. (Maybe the houses were structured teams sent to find the traveller again?) the houses then go out trying to find the traveller but become savage without its light. They become pirates and in that forget what it was they're primary goal was from the beginning. Now we fight with them to protect the traveller just as they probably once did. Hive: I'll start by prefacing read the book of sorrows or at-least someone's summary of it. Now let's dive into it. The sisters go to the worms the worms change them into the hive in short. But why did they go to the worms? Perhaps they once too had a traveller and upon its leaving they descended into the dark ages and upon looking for structure and order thy created a monarchy. Upon the Kings death the three sisters go to the worms and the worms basically transform them into a species that in fact embrace the darkness. Looking to destroy the light and all things derived from it but I believe this is the influence of the Wyrms. Wyrms: basically the worm race that spawned the hive race. Many have noticed the similarities between them and the ahamkara. We know from grimoire that the ahamkara began appearing on earth upon the arrival of the traveller. They were hunted into extinction. I believe he Wyrms were ahamkara that became plagued by the darkness once the traveller left. This probably would have happened during our dark ages had we not hunted them into extinction. As for the cabal I don't believe they haven't been exposed to the light of the traveller and have yet to go into a golden age. They have probably however heard of it so the cabal empire created forces to search for the traveller in an attempt to take it. The cabal are in a highly militarized state which is why I believe they never had a traveller because without knowledge people resort to violence. The vex however are a mystery to me. Perhaps the were created by another race during a golden age of the traveler and upon its exit they became corrupt with darkness but they still have the basic program to build and expand. These are just some thoughts so add in if you want I'd love to hear others theory's!