The Hive will be especially prevalent in the Dark Below DLC.
Unfortunately much of the game’s lore is hidden within the Grimoire cards. Thanks to Reddit user KentsFood, he’s compiled information & lore about the Hive (mostly from the Grimoire), which you can read below.
The Hive are an ancient, festering evil. Their antipathy to the Light transcends hatred. To the Hive, the eternal struggle between light and dark is not only a war, it is a crusade—all Light must be devoured so Darkness can reclaim the universe.
Hive Sects: Blood of Oryx, The Scarlet Brood, Spawn of Crota, The Hidden Swarm, Venom of Oryx.
Conflict is not always cleanly black and white; there are complexities, shades, and arguments for either side. But there are no arguments for the Hive. They are pure evil, and they seek to destroy humanity.
The Thrall are a plague. The basic units of the Hive, they are deployed in swarms that charge guardians and claw at them. The document refers to Thralls as “frames”, indicating that the Hive “rank up” their soldiers by adding more and more armour onto the Thrall. However, it could just represent the phenomenon that Hive corpses undergo.
Where Thrall are the bullets, an Acolyte is the barrel. Acolytes are not merely footmen, but instruments of the Hive’s dark will. They hunger to commit the atrocities that will lead to the Hive’s success.
Knights are the Hive’s defenders. Centuries of battle harden the bony spikes on their body into armour as hard as relic iron. Knights are bolstered by Hive magic to further increase their abilities. Knights wield an armoury of weapons: Boomers that lob bolts of rotting star fire, Cleavers that are massive but are swung with ease, as if hungry for Light themselves.
Ogres are abominable creations fuelled with magic and rage. They are found in the deepest Hive tunnels and formidable opponents to any Race, Fallen or Human. Rumour has it that Ogres go through ritualistic transformations as they grow, imbuing them with might and cunning (and the ability to shoot void beams out of their foreheads, how they do this is unknown, but it should not be underestimated.)
Wizards names are misleading, as they are exclusively female. They are scientists and sorcerers. Wizards experiment on whatever they can find and shield themselves in Fire and Darkness. During the reign of Crota, a Wizard was captured and interrogated, ultimately giving up the secrets to destroying the God.
Shriekers are neither a machine nor are they organic. They are dead mass, animated by the magic of the Hive. When a Shrieker is destroyed, its inner Void seeks vengeance on those who did so. Some believe Shriekers to be the eyes of the Hive, allowing Wizards and Knights to watch over the battlefield and inner workings of the Hive’s extensive tunnels. Some believe to them to be nothing more than weapons, guarding important Hive areas.
Seeders are enormous spears full of Hive that pierce a planets surface and unleash their horror upon it. Reports of Seeders being found on Earth are concerning, indicating that Hive may be looking to eliminate the Light, once and for all. A mission to the World’s Grave uncovered that the Hive have in fact been seeding Earth for centuries. Guardians wishing to uncover more about them can find on buried in Skywatch, near the infamous Treasure Cave.
The Hidden Swarm are distinguishable from their red Knights and Wizards. The Hidden Swarm are the Hive’s outer line of defines. They have infinite resources, and are tasked with repelling threats before they breach the massive Hive Fortress on the Moon. The Hidden Swarm are found on Earth too, sent in Seeders.
The Spawn of Crota are a worrying threat. They have armour of gold, and are led of the champion of a long forgotten King. Crota. Crota was a Knight, A terrible Lord that wielded a powerful relic, The Sword of Crota. Forged by the Swarm Princes, the Sword is a weapon capable of devouring the Light of Guardians it kills.
The name Crota was discovered by an Exo Warlock, Eriana-3, who interrogated a hive Wizard during the battle on the Ocean of Storms, where Crota marched with a thousand Knights upon the Guardians who stood to defend it. Ultimately, Crota was defeated, but we were forced to give up the moon for fear of his wrath.
The Sword was retrieved by Guardians, who defeated the Swarm Princes with their own weapon. Rahool, master of the Cryptarchs, believes that Crota’s return is inevitable, we are now one step closer to defeating the Hive, and retaking the Moon.
The Cryptarchs believe the Hive serve one Master. The Blood of Oryx are believed to be the direct descendants of Oryx, their Dark Lord. Guardians destroyed a Shrine of Oryx, guarded by Sardok, the Eye of Oryx, deep within the Hellmouth.
An old Warlock, Osiris, knew/knows of the threat of Oryx and asked Guardians to destroy the Shrines should the ever find one. It is said that there are Shrine scattered throughout the Solar System.
A dying Ghost was uncovered by a Guardian storming the Temple of Crota. The Ghost left a text file before it perished. The Hive ate it’s light, and the Ghost was interrogated by a Wizard. The Ghost reports that the Hive gain their strength from something other worldly, a force that corrupts, distorts and eats.
The Worlds Grave is a Hive Library, containing all of the Hive’s knowledge. Guardians broke into the Worlds Grave to find out what the Hive knew of Earth.
The Hive had so much information they had “Broken the Bekenstein Limit” (The maximum amount of information that can be contained within a finite region of space with finite energy. This suggests one of two things, either the Hive can travel dimensions, or they have access to unlimited energy.).
The mission uncovered the Hive’s invasion plans, as well as information on their Gods.
Guardians uncovered a Hive ritual, where they had obtained a shard of the Traveler and had Siphon Witches infect it with their dark magics, slowly killing it from the inside. The ritual was well protected, as the Hive kept an Unborn Ogre, Telthor, on guard there.
Unborn ogres are those who have not gone through a Summoning, and seek to display loyalty and strength to become Reborn. Unborn are kept hungry and chained, that their brute strength might be increased because of it.
Deep within the Summoning Pits, Guardians found and killed Phogoth, an Ogre going through a Summoning to hone it’s rage and misery and direct it at Earth. The Strike against the Hive will prove invaluable against the fight against the Darkness.