Here is a theory for you... What if the Traveller is nothing more than an AI in a terraforming ship, sent ahead of a colony ship. But somewhere along the way the colony ship doesn't arrive. Terraforming ship decides to find someone else to help colonise worlds... Traveller finds us... but what if ANOTHER Traveller was out there... a Black Traveller who terraforms the planets the Fallen originally were on... before they became the fallen. The terraforming engine infects the Pre-Fallen and create the Hive... which is why the Hive and the Fallen are fighting... The Hive drove the Fallen from their home planet and then follows them. The Fallen will then hate the Terraforming ships... including our Traveller. The Hive just plain hate everything, being space Zombies after all.

Maybe the traveler gave several of the races its light once and they misused it? Now they are trying to destroy humanity in fear of our capabilities.

Did everyone forget that the hive make temples on the moon giant spaceships and all that sortve stuff? I don't think the hive are zombies I think more like the aliens from e movies: alien vs predator and aliens and such. I mean they wernt zombies but they had a queen made structures had classes and so forth "Ty god they didn't make spaceships D:" just like how the predators made the aliens I just think the darkness gave "it's light" to the hive to make them a sentient specious but I don't think they're zombies and I think the two armed fallen are females they're smaller n there body structure couldn't spport two extra limbs and they have a Mohawk I think they're females and the four armed ones are males btw hope this cleared up this whole confusing thing about the hive being zombies

I do remember that the first thing I thought of when I saw the traveler, was of a terraforming module.. but for what..? I do like the theory of the hive being fallen, and I assume we'll see more hive zombie types.. perhaps we'll even see hive infested guardians...

I highly doubt that the Fallen and Hive are related in any way. The Fallen do not directly serve the Darkness, for they fight the Hive--and the Hive embrace the Darkness and revere it. The Hive are undead. They are not an infection or biological entity like the Flood from Halo. They are necromancers who have used the power of the Darkness to keep themselves alive for eons--they are directly inspired by fantasy undead. The location of "The Summoning Pits", and the mention in a patrol mission that "space barnacles" are biomass grown by the Hive makes me think they grow corporeal forms from this biomass, which they in turn bind summoned souls of old to. They are an ancient monarchy that has preserved their hierarchy through millennia of undeath. Thralls, Acolytes, Knights, Wizards, Ogres---and perhaps more enemy types we haven't seen. They are a race of liches. Why are they undead? Perhaps they hit a snag in their own evolution when they were truly living, and turned to the Darkness to preserve them as they saw it as the only way to escape extinction. Or, perhaps they were so corrupt and greedy for eternal power when they encountered the Darkness that they simply embraced it. The Fallen on the other hand are completely biological. They don't show any signs of being undead despite their souls escaping from their bodies when killed. They had a grand past which they scarcely cling to; they are now nomadic barbarians that pick apart whatever they find. They assert what's left of their former authority and nobility onto whoever gets in their way, for they have claimed all of our former worlds for themselves. They think they are still entitled to riches and glory, and since they have none left, they resort to forcefully taking it from others. They are divided amongst themselves into five Great Houses. Unlike the Hive, their physiology is different. Their limbs may be similar, but their head shape and eyes are very different from the Hive. The Hive come in all shapes and sizes--the twisted frames of the Thralls, the hunched-over Acolytes, the upright (and tough) Knights, the floating Wizards, and the Giant Ogres. But the Fallen (apart from their servitors) have the same basic shape across their ranks. Also, it's highly likely the Fallen's current nomadic raider behavior is a much more recent development than the Hive's necromancy. I still don't think there are enough similarities, even for them to share a common ancestor. Their origin stories are just too different.