Alright here it goes... Crota is either The Darkness or a high-ranking enforcer of some sort to The Darkness. While Crota may create the hive, the hive don't just come from thin air... they are created from Fallen and Cabal that have been corrupted and consumed by The Darkness, here their likenesses as well as the cooperation by the Fallen and Cabal. But what about the Vex? The Vex don't just come from the future, they come from a parallel timeline in the future where Humanity has already by consumed by darkness... because they are humanity consumed by darkness! OH -BLAM-! (We know the Vex are at least partly organic) They come back before the split in the timeline not to destroy us, but to thrust us into darkness. Why? Because why would The Darkness settle for just one reality? So now you have the Fallen and Cabal fighting the Hive and Vex because Darkness. And they want to destroy us because somehow they've figured out that we may become Vex.

ok I want to know something so reef huh? nobody knows about it and its not a plaent in our solar system for sure so what is it im thinking that maybe its the place where the darkness is waiting for a strong guardian to face him or her whatever it is just saying I mean what is reef for sure?

If you read the Destiny issue of Newsweek, it clearly states that the Hive are a race born inside the darkness. While the Fallen are a once noble race, corrupted by the darkness. The physical similarities are mute. Look at many races from Mass Effect, they had the same 3 fingered hands and 2 toed feet, yet shared no common ancestry. It is most likely just an evolutionary coincidence. The descriptions come strait from Bungie.

My theory is that the hive are in fact fallen who were corrupted by the darkness. in the fallen lore, it says they were once noble houses but due to some unknown event collapsed and became the pirates we know them as today. I think that the fallen were visited by the traveler at some point in there time line and when the traveler left the darkness came and destroyed the fallen and those it destroyed, it brought back in the form of the hive. keeping with the lore of destiny, the traveler represents light, while the darkness... well the dark. it would stand to reason that the 2 would have equal and opposite powers. were the traveler can bring you back to proper life, the darkness can only bring you back as a form of the undead. the vex are possibly from a point further in the past rather than the future sent forward in time as a way to combat the hive/darkness by any means necessary, including wiping out the other races to prevent more hive from being made(similar to the forerunners plan on how to deal with the flood). as for the cabal they were possibly a more peaceful race but after the traveler and subsequently the darkness came they became more warlike and militant. through these examples you also see similarities between the factions and the other races. the dead orbit being like the fallen who left their world in order to survive. new monarchy being like the cabal. and the FWC being like the vex in that they wasn't to use some form of time travel or are preparing for such a thing, in order to change the outcome of events. I realize this is all a very long stretch but it does make for a very compelling case once you look at them and their dialog from the beta. on top of this in the beta some of the grimore cards were specific to a class of enemies under the name darkness. this is most likely an unrevealed class of enemy similar to the guardians but only in an obviously more dark and sinister form. foes super charged with the power of the dark sent to destroy the guardians of the last safe city.

They have similar humanoid anatomy because that makes it easier for the game developers to create animations off of the same framework. My 0.02$.

I don't know what's in them, but in the moon, there is a massive chamber filled with rows upon rows upon rows... you get what I mean, of cocoons, eggs, or something on that line. So it's completely iffy on what the cocoons are for, but I believe it would most definitely shed some light. Maybe the cocoon is where they do take the dead, or maybe they are egg sacs laid by a queen. Which supports why there are such large spaces, the mindlessness of the thralls, and why they are expressed as knights, acolytes, wizards, etc. But if there is a queen, I bet there is a 50% chance of a king, and I don't want know how strong that is.

"Corrupted" would imply that the Fallen existed prier to their exposure to the darkness. I wouldn't be surprised if the Traveler found them, as it did with us, but the Darkness caught up to it before it had a chance to protect them. Saying they were "once" a proud and noble race seems to imply that the Fallen had their own Golden Age. But the Traveler had to abandon them, leaving them to the darkness. As for the Hive being "born in" the darkness, it seems to be that by the time they evolved to their current forms, their home world was already taken by the Darkness. This could, in turn, explain why the Hive units are all so different from one another. They are actually from different species, but the same planet. This could also explain the conflict between the two races. One is the Darkness' "created" children, while the other is its "chosen" children. Their hostilities could be born from a religious point of view. They are both driven by the Darkness, but have different feelings toward it, which is why they will stop fighting each other to fight the Guardians, the enemy of their "GOD".

The support base centered here was likely the first off-Earth colony, though it has long been left to ruin. In the centuries since, Hive temples have begun to breach the surface, exposing entrances to their fortress below. [b]It was here that we came face-to-face with Crota and his legions, a force so powerful we abandoned the Moon.[/b] Now Guardians venture into its depths seeking revenge, most never to return. the hive have been on the moon before ?

Why is everyone so sure that the fallen is the hive? You do realize that the hive actually are insect like, and so that the thralls are just simply worker ants for the colony? No brain required for lifting a pole. Acolytes are actual overseers for the thralls, knights are the "titans" of the hive, wizards or commanders, most likely with an actual brain, used for coordination of hive forces. Orgers are literally tanks, looking at one chained in a video, most likely completely brainless, and need to be carefully monitored so they don't smash other hive. Great chance of a queen because of eggs found. Also, why would they want to convert other races? They despise other life, and want to eradicate it all. Their crusade of darkness? Am I the only person who watched the video for them?

This made me think of the factions in the tower. The faction leaders expressed their philosophies to respond to the coming darkness. this video from dattodoesdestiny has clips from the faction leaders: https://www.youtube.com/watch?v=F7HRgOwzr_M&list=UUkmAjbIecTIjTQctolYeuDw&index=2 Dead orbit wants to run and hide from the darkness - they remind me of the hive The new monarchy wants to build a new kingdom - they remind me of the fallen The future war cult that wants to fight until they are wiped out - they remind me of the cabal or their obsession with another timeline reminds me of the time traveling vex. Perhaps the characteristics of the enemy species we encounter are a representation of choices those species made when they encountered the darkness. Or maybe in some weird way the species we fight against are actually ourselves from different timelines where we made different choices.

I think it's a coincidence that the Thralls and Dregs/Vandals look the same it's possible that they originals wanted the Hive to be space zombies that resurrected dead species like the Fallen. However if that was the case they'd be adding humans and guardians to their ranks along with the Cabal but they aren't. If you look at the Hive they all appear to have exoskeletons, They have rooms filled with egg sacks ,and have a tiered hierarchy like a monarchy; you have the Thralls which means slaves, Acolytes meaning assistant or follower, Ogres meaning hideous man eating monster/giant, Knights meaning someone who serves a sovereign lord, Wizards meaning someone with magical powers. The Hive sounds a lot like Arthurian legends by that tier system and since they're the "Hive" which is something created by insects and going with their exoskeletons, egg sacks, and tiered hierarchy everything points to them being insects so they must have a King and Queen that we haven't seen. Also I just remembered if you kill a Wizard the other Hive under them usually die so they must have a psychic link or something similar to what most insects have and the Wizard with their powers are a lightning rod for that link picking up the signal from the Queen and King and sends it to the Hive beneath them and vice versa so when the Wizard dies and the Hive dies with them that's because that psychic link shuts down and they don't actually die but go into a hibernation state until another wizard comes by.