A couple of thoughts I've had since beating CsE and reading that Grimoire card (forgive me if I ramble here). I find it hard to believe that they would put this in the Grimoire just for kicks. Someone obviously took the time to create these cards, so I feel as though every line is purposeful and important. So let us assume for the moment that they are indeed connected, and figure out how that could work with what (limited) knowledge we have of the story/universe. It says that the realm in which we fight Crota is a Hive netherworld, or some other dimension that the Hive are able to occupy. We also know that the Vex use some kind of trans-dimensional technology for their own purposes. The Vault of Glass itself seems to exist within its own dimension of space-time. Also Grimoire cards for Vex weapons mention that they are powered by forces outside of our solar system or space-time. Specifically, it mentions a star or black hole (this will become very important later, so keep it in mind). In the Shrine of Oryx mission, the shrine itself is said the be connected to some power source beyond our solar system. So in this we see similar uses of technology by the Hive and Vex. This got me thinking about the Crota fight itself. Not really the fight, but the environment. In the background, there is what appears to be a cracked planet or moon with a black singularity at its center. You know what else it looks like? (Please put on your tinfoil hats now) A broken and cracked open Traveler. This brought me back to a theory I read here in the early days of release. Full disclosure, this is not my theory, if I remembered who first said I would be give them credit but I don't. Just to say it again, I did not come up with this theory, I just remembered it and applied it to what I'm going to say next. The theory was that Oryx and the Traveler were individual members of the same species. Maybe the last two, who knows. In any event, they had obvious philosophical differences about the universe and went to war with each other. But visually, you wouldn't really be able to tell them apart. This is where I put that together with my original thought that the "moon" in the Crota's End looked like the Traveler. What if that thing is actually Oryx? Broken from it's battle with Rasputin and the Traveler but not defeated, it retreated into a dimension where it could heal, where its minions could protect it. Could this be the source of the trans-dimensional energy for the Vex weapons? Could it be the power beyond that the Shrine of Oryx was tied to? Of course we don't have definite answers, but I think it's likely. In summation, the connection between the Vex ad Hive seems to have an explanation, although it does take some theorizing and tinfoil hat reasoning to get there. Again, I firmly believe that every word in every Grimoire card was put there for a reason, and that they wouldn't mention that possible link if it didn't actually exist and get us doing exactly what we're doing: discussing it.

If VEX + HIVES had a baby = The Predator

Gee an underworld sounds like a fun place to patrol too bad bungie is literally hitler

What it REALLY says is: "The nature and possible interrelationship of the Vex gate system with Hive netherworlds remains unexplored."

Also, in ghost fragment: hive 2, the narrator is bring draoned of their light by a wizard. Maybe this is the person we see outside the temple in the first mission or Omar, one of Eris's fireteam. I found this interesting thing in the grimoires too.

All I know is that the vex launched a massive attack on the hive home world (which is where you fight crota). That's why everything there is so screwed up

on youtube there is a destiny lore series look it up very descriptive and its all based on the cards no theories just some interesting tidbits for those like me too lazy to read the cards https://www.youtube.com/playlist?list=PL8CeKNIbQ62Wk0W0ibLVf8rOCW-VcGZLl

I haven't read much grimore, but they could be connected in some way. They are never seen fighting each other either. The fallen and cabal fight the vex. But the hive never attack the vex. They could just be on separate planets...just my thoughts...

Hive ships teleport in just like vex teleport in maybe they use the same system

With Bungie's storytelling prowess, this will be the only mention of any connection between the two.

Illuminati confirmed.

Hive ships come through portals where each other ship has to fly in from the distance. AKA hive are the only ships that teleport like the vex.