How do you know who osiris is talking about?

Dissect his words. "The first comes in a shadow." The shadow of the traveller "A window becomes a door. " Space. The final frontier. Something we could, at one point, only dream of going to its far outreaches in exploration. Something we could only look at to. like a window. But now, we can enter/exit whenever we please. Like a door. "An ebb becomes a gulf. " A receding small wave (the first guardians after the collapse), or an ebb; become a great gulf capable of pushing back "The second come in bones" The hive are but culminations of bones. Forever rotting and peeling to the bone, but never dying. "Tithes offering feasts; carrying laws" In the hive hierarchy; everything must tithe a part of its power to a higher entity. Thrall will kill, and feed their worms; then tithing some of their gain to acolytes above them. So on to the knights, then ogres, then wizards, then deathsingers, then the hive gods, all the way to the worm gods. "Path torn, mind shattered" We see in a grimiore card where quria fails at simulating a version of oryx, and instead simulates an aurash. The simulation of aurash is more than displeased with what she becomes. The path she wished to saunter has been torn. And oryx's mind over the years has unraveled. "The third does not come alone. It cannot" All vex units operate under an axis minds. They never fight alone. They are incapable of it. Where there is one unit; there are millions more. "Our truths woven into their being, desires beyond our own." As it has been insinuated for a long time; the vex at one point did assist the traveller and humanity, via terra forming the planets. Though sometime around the collapse; they were corrupted (and they also corrupted) the darkness. They, like humans, wished for a perfect universe. They wish for transcendence. They just wish to go about in a bit more of an extreme manner. Now; just go back and fill in the names for the variables. [b][u]"we come in a shadow.  A window becomes a door.  An ebb becomes a gulf.  The hive come in bones.  Tithes offering feasts, carrying laws.  A path torn, minds shattered.  The vex donot come alone. It cannot. Our truths woven into their being, desires beyond our own.  Guardians need the second to fail, the vex needs the guardians to succeed. The hive will never cease, yet the guardians always prevail. The vex are born of all outcomes. Unless, all ends flow from the same pit. "[/u][/b]

Why was he more inclined to studying Vex than if he felt the hive was the biggest threat?

Osiris didn't only spend time studying the vex. He was slightly invested with hive as well. I can only assume his greater intrigue in vex is due to the fact that - excluding us, the ahamkara, and perhaps the nine - the vex are the closest to being a true threat to hive. More so; ever since quria's fall, their axis minds have been attempting to find a way to best them without using sword logic. And they actually got close. That is a monumental achievement. Whilst in their current form vex are very incapable of defeating the hive; if they were to find a way of defeating the pinnacle of sword logic without assimilating it (like we have) That could mean a plethora of things. The end to the hive; or perhaps the WORM GODS! In other words bringing them that closer to making darkness itself bleed without being a part of either side of the spectrum

Or that Osiris knows something about the Vex that we don't, that they can can live in symbiosis or even allied. That they have only logically deducted sword logic is king of this dimension because of Qurias defeat and that if shown it's not, they could logically deduce to change their mind. This could explain the trinkets the Osiris disciples leave on Vex architecture, they could be gifts of art and beauty or peace offerings. That destruction is not the only way.

Perhaps, but unlikely. The vault and black gardens are pieces of reality in which the vex see as not only "perfect", but unique. Between all dimensions and timelines the vex have traversed they have only found one version of each. Thus; these were seen as ways to attain their transcendence. In fact that was one of Atheon's directives. To bring the vex's full ontological and paracausal power outside of the vault. Though this obviously never came to fruition. And even if it did; it is plausible it might not have worked in their favor regardless. Again, when the taken entered the vault; the vex calculated that they alone could not defeat them. Even in a dimension where they control what and what does not exist

Or that they simply calculated that we could help them.

No. The vex are an entity that wish to be only itself. It has no reasons to commit symbiosis, and wouldn't like to have "help" They want things that are perfect They do not see us as perfect In that moment; they just required a mediator so the hive/taken would not end them

They may be of an organic base, but something still had to program them . There's no way radiolaria could have evolved into a robot body. If they were programmed, then they can be reprogrammed.

Cool. I too think that, after reading the Books of Sorrow, the Hive is the strongest of them all. It is actually a bummer that feeble guardians as ourselves could defeat such an overwhelming being as Oryx.

We weakened Oryx a BUNCH before we actually fought him. We cut off his tribute from Crota, his Daughters, the Warpriest, Golgoroth, his Court, and a helluva lot of other Ascendants and lesser Hive. We took the Shrine of Oryx on the Moon out of commission. Oryx relied on them for power; without them, he could not generate enough killing and tribute to feed his Worm, and it would consume him. When we fought him, he was pretty much dying already.

Makes sense. I remembered I saw somebody's post going on about how Oryx's worm (Eir?) is already eating on his essence when we face him in his throne world and drew a parallel between it and Touch of Malice. Pretty interesting stuff.