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The Worms are an ancient, parasitic worm-like species aligned with the Darkness.
The Worms are disciples of the Darkness and draw their power directly from it. It is through a pact with the Worms that the ancestors of the Hive became the Hive and launched their conquest of the whole universe. The Worms are worshipped and revered as the Hive's highest deities, beyond even Oryx, the Taken King and his sisters Savathûn, the Witch-Queen and Xivu Arath, God of War. All Hive are bound symbiotically by a larva from one of the five Worm Gods, which drives them to feed off constant conquest and destruction lest the Worm grow unsatisfied and consume them instead.
The origins of the Worms remain a mystery. However, according to the Darkness, in the primordial state before time or the universe began, entities existed which derived sustenance from the gradient between "what was and what might be." This may hint at the origins of beings such as the Worms, which continue to base their existence on the difference between actual and possible realities.
The Ancient Past
Billions of years ago, the Worm Gods were trapped deep beneath Fundament and guarded by the Leviathan. One of their dead larvae eventually washed up on the shore of the Osmium Court, where it was found by the proto-Hive Osmium King and taken as his familiar. Following the Osmium King's murder by the Helium Drinkers, his daughter Sathona took it from him as she, Aurash, and Xi Ro fled the Court. The dead worm spoke to Sathona, and through her guided the three sisters in their quest for vengeance.
Eventually, the worm led the sisters into the depths of Fundament, to the domain of the Worm Gods, who tempted them with power and immortality in exchange for becoming parasitized by their larvae. The sisters accepted, taking on the names Auryx, Savathûn, and Xivu Arath. Acting in concert with the Worm Gods, they took more larvae back to the surface in order to offer the rest of their species the same bargain. Those who refused to accept were killed by the emergent Hive.
The Worm Gods oversaw the Hive's conquest of Fundament, providing knowledge, orders, and censure to their leaders as necessary. When the war freed the Worm Gods from Fundament's core, they responded by opening a wormhole into geostationary orbit, allowing the Hive to invade Fundament's moons and the Ammonite civilization that dwelled there. The Hive eventually exterminated the Ammonite and slew the Leviathan. Eir and Yul consumed their captor's corpse. After this, the Worm Gods withdrew to the Ascendant Realm and generally left the Hive alone.
Auryx would later seek out and slay Akka for the knowledge to commune directly with the Darkness. He returned as Oryx, the Taken King.  However, Akka remained active in some fashion and battled Oryx following the events of the Golden Amputation. At some point Oryx recovered a fragment of Akka's shell and used it to craft his Dreadnaught.
Sometime after the death of Akka, Yul began to contemplate taking the power from the weakest of the four remaining Worms, in order to withstand any future attacks by Oryx. Knowing himself to be vulnerable, Xol, Will of the Thousands made a pact with Oryx's abandoned son, Nokris, to flee Fundament and seek new worlds to conquer together.
Many years later, upon the frozen ice caps of Mars, Xol's physical form would perish at the hands of the Guardians, along with his herald. As with Akka before him, Xol transcended death and would go on to present himself to a group of Taken on Io, who offered him worship and service. After the Guardian proved themselves to Xol, he drew upon his power through the Sword Logic, transforming himself into the Whisper of the Worm.
The Worms are a parasitic species, entering into symbiotic relationships with other sentient races in order to amass greater power for themselves. As larvae, they can inhabit the bodies of other beings, such as those of their servant race the Hive, and "feed" off the power acquired by their hosts through following the Sword-Logic. Worm larvae are pale and about a meter in length, with rounded heads, six short spines on their back, and two spines at the end of their tail.
It is unknown how long it takes for Worm larvae to mature, as Oryx, the Taken King, along with his sisters Savathûn and Xivu Arath have been feeding their worms for potentially billions of years, yet their worms had not matured.
As adults, Worms can reach tremendous size; Xol, the first of the five Worm Gods encountered by the Guardians, was hundreds of meters in length, and the size of the Dreadnaught suggests that Akka (one of whose segments was used by Oryx to craft his flagship) was orders of magnitude larger. Fully grown Worms are covered with segmented plates and numerous spines, and have heads with six barbed mandibles surrounding glowing eye-like structures.
Notably, the Worm God Yul describes himself as having wings, while Xol is not seen to possess wings when encountered on Mars. This may suggest that only the largest and most powerful Worms possess wings, as Xol is implied to have been the least powerful of the Worm Gods.
List of appearances