I posted this on Reddit a while back, and I thought I'd post it here too. Before really getting into it, let's establish some things so everyone is on the same page. 1) The Hive possess symbiotic/parasitic worms that make them biologically immortal, and the worms are agents of the Darkness who taught the Hive "magic." 2) After making the pact with the worms, the Hive gained access to sword logic. Sword logic is a paracausal (beyond physical laws) mechanism through which the Hive gain power, even godhood, from killing. [quote]OBLIGATIONS. Once, I permitted Oryx to kill me so that he could gain the sword logic and overcome Akka our God. This left me trapped deep in my throne.[/quote] 3) The Hive must feed their worms through killing. [quote]“I am at my end,” Savathûn says. “I plot and plan. But I cannot gather enough bloodshed to feed my worm. And the harder I try, the hungrier it becomes.” (Book of Sorrows, Verse 3:6)[/quote] There's also this. [quote]You Thrall, each of you will claw and scream, and kill what you can. Take enough killing to feed your worm, and a little more to grow. Tithe the rest to the Acolyte who commands you. You Acolytes, lead your Thrall in battle. Take enough killing to feed your worm, and a little more to grow, and take the tithe of the Thrall you lead. Then tithe the remainder to the Knight or Wizard who commands you. Thus you pay tribute. You Knights and Wizards, lead your followers in battle. Take enough devastation to feed your worm, and a little more to grow, and take the tithe of your followers. Then take another portion, as much as you dare, and use it for your own purposes. But if it is too much, your peers will kill you and take it. Then tithe the remainder to the Ascendant you serve. An Ascendant will be those among the Hive who gather enough tribute to enter the netherworld. They will pay a tithe to those above them. And thus the tribute will flow, up the chain, so that Savathûn and Xivu Arath and myself will be fed by a great river of tribute, and we will use that excess to feed our gods, and to study the Deep. Thus all worms will be fed — as long as we continue our crusade. (BoS, Verse 3:9)[/quote] I used to wonder exactly what tangible substance (not just "killing") the Hive were feeding their worms with. From the quote above, it's something that could be taxed and passed up the chain of command in a tithe system, so the abstract concept of "death" and "killing" wasn't a satisfying answer. Before Warmind, I thought the answer was Light. The Books of Sorrow has numerous references to eating the Light, and Dredgen Yor implied that all living things have a spark of Light, so it made sense to assume that the Hive feed their worms with the Light of their victims. [quote][u.2:6.4] You have no Light beyond the spark of your pathetic life. [u.2:6.5] But a spark is something. (Ghost Fragment: Thorn 2)[/quote] I discovered the real answer during the Warmind campaign. In Strange Terrain, we find the Hive using crystals made of the solidified green flames known [b]soulfire[/b] to feed the wormgod Xol. Soulfire seems to be that tangible wormfood substance produced by killing. Even beyond feeding the worms, soulfire seems to play a major role for the Hive power. Enraged Hive knights and fire-casting acolytes burn with green soulfire flames, Hive spells and seals glow green with soulfire, and in his throne world, the Hive god Crota appeared composed of soulfire. Hive even explode with green flames when they are killed with headshots. This all suggests that the powers of Hive are tied to soulfire. Since Hive power comes from sword logic, and soulfire seems to be the form this power takes, it stands to reason that soulfire is a product of sword logic. Interestingly, another passage from the Books of Sorrow links power gained through sword logic (cutting passages through space) to soulfire. [quote]SAVATHÛN said, Auryx my brother and king, I have studied the wounds cut by the Worm our God. Also I have studied the manner of your death and return. These two things are the same, for they are predicated on death and the passage through cut spaces. Let us practice the sword logic until we are sharp. We may then cut our own wounds and step through. But XIVU ARATH said, sister, I am already sharp, look, my sword cuts into another space. And she cut her way between moons through [b]green fire[/b] and joyous screams. (BoS, Verse 4:5)[/quote] The first quote under 3) from Savathûn illustrates the ever-growing hunger of worms, so how is Nokris and his army killing enough to make the soulfire needed to feed a gigantic worm god? Where is all that soulfire (and by extension, killing) coming from? The answer lies in Nokris' necromancy. During the Strange Terrain strike against Nokris, Ana Bray sometimes says this: This Nokris is even worse than we thought. We're talking [b]necromancy. Endless cycles of death and rebirth, all in the service of a giant worm god[/b]. I believe Nokris kills the Hive under his command, brings them back to life, and repeats this process to create the "endless cycle" Ana spoke of. This allows him to produce vast quantities of soulfire from simply killing the same few Hive repeatedly. There has to be some kind of diminishing returns or limits on this practice though, or Xol would have been a lot more powerful. [b]TL;DR - soulfire is a type of substance generated by the Hive when they practice the sword logic by killing. Soulfire is used to feed worms, but also it's energy source for Hive powers and spells. Nokris uses necromancy to kill and resurrect the same underlings repeatedly, and this killing grenerates soulfire used to feed the wormgod Xol.[/b] [b]For more theories by me, I refer you to the [url=https://www.bungie.net/en/Forum/Post/183288968/0/0]Collected Treatises of The Warlock KAGEHOSHI[/url].[/b]