Hellmouth

The Hellmouth is a location on the Moon that refers to both an underground fortress constructed by the Hive and the area of the Moon's surface surrounding the massive pit that gives the fortress its name. It serves as the main staging ground for the Hive god Crota and his forces for their invasion of Earth. The Hellmouth features an inner sanctum, gatehouse, and dungeons that are located in the depths of the fortress, imprisoning the Hive's most fearsome denizens.

Overview
The Hellmouth's many underground passages reach far and deep into the Moon; besides the main entrance through the Gatehouse, it also has tunnels connected to the Temple of Crota and Archer's Line. Within the Hellmouth itself is a labyrinth of chambers for various purposes; The World's Grave, containing the Hive's collective history and many of their secrets, the Chamber of Night, where the Hive perform profane rituals, the Summoning Pits where Phogoth, the Untamed is kept chained, the Shrine of Oryx where the Hive contact their mighty king, Oryx, the Taken King. In the deepest, darkest pit in the Hellmouth is a rupture leading to the Oversoul Throne, the throne world of Crota, Son of Oryx.

Two years after the Red War, the Hellmouth is still a prominent Hive Stronghold on the moon, now entirely under the guard of the Hidden Swarm instead of the Spawn of Crota. Parts of Hellmouth's structure seem to have been stripped apart, presumably to construct the Scarlet Keep.

History
The Hive are known to have invested the Moon for hundreds if not thousands of years. They would slaughter inhabitants of the Moon during the Collapse. After the Collapse, Hive Forces of the Hidden Swarm, Spawn of Crota, and the Blood of Oryx led by Crota, Son of Oryx would conquer the Moon and fortified what would become the Hellmouth. They would begin their plans for an invasion of Earth.

The City Age
During the City Age Hive forces would arrive on Earth and occupy parts of the planet, including the Rusted Lands where the champions of the Traveler would first discover there presence. Legendary Hunter Rezyl Azzir would arrive on the Moon and confront the Wizard Xyor, the Unwed who prophesied that he would fall. After Rezyl succeeded in killing Xyor’s consort he took the Knight’s chitin to adorn onto his gun Rose before he returned to the City. This artifact would corrupt him, he would befall to the whispers of Xyor and become the ruthless tyrant Dredgen Yor. After the Battle of Burning Lake where the Hive were defeated. The Consensus decided to launch a counterattack on the Moon despite the protests of Shaxx. An army of hundreds of Guardians would arrive on the Moon. However Crota, Son of Oryx led a counterattack against the Lightbearer’s. Hundreds of Guardians including Wei Ning were slain by the blade of the God-Prince. The sky of the region turned into green fire and the surface of the Moon was cracked by the wrath of the World Breaker. The Vanguard would order all surviving Guardians to retreat and declared the Moon of limits, this catastrophic event would be forever marked as The Great Disaster. After the death of one of Oryx’s generals in the Ascendant Plain, Crota would decide to sleep in his throne world to recover strength, putting his soul into an Ascendent crystal in his temple, and trusting his sword with the Swarm Princes. The Wizard Mormu, Xol Spawn would create the Crota-spawned Ogre known as Phogoth, the Untamed. Later a fireteam led by Great Disaster surviver Eriana-3, alongside Eris Morn, Omar Agah, Sai Mota, Vell Tarlowe, and exiled Warlock Toland, the Shattered infiltrated the Hellmouth. Tho they succeed destroying Crota’s physical form, the Hive would hunt down the members of the fireteam. Only Eris Morn who’s Ghost was destroyed, and Toland, the Shattered who became an Ascendent spirit survived. Eris survived in the Hellmouth for years and eventually escaped, seeking to take revenge on the Hive for the death of her fireteam. After the Battle of the Twilight Gap the House of Exile was formed on the Moon and often come into conflict with the Hive

A Guardian Rises
When a newly risen Guardian arrived on the Moon they would travel to the Temple of Crota learning from a dead Ghost of the Hive’s planned invasion of Earth. The Guardian would continue to infiltrate the Hive fortress, they would steal data from The World's Grave, slay the Swarm Princes with the Sword of Crota which broke afterwards, and killed Sardok, Eye of Oryx, destroying the shrine of the Taken King in the process. The Siphon Witch’s of the Hidden Swarm began a ritual to drain the Light from a shard of the Traveler where they would once again be stopped by The Guardian. Later a fireteam would be sent by the Vanguard to kill Phogoth, the Untamed

The Dark Below
"Six of us went down into the pit. Only one crawled out. I am Eris the last. I have seen what the Hive call a God."

- Eris Morn

The disciples of Crota, led by his consort Omnigul, Will of Crota would their begin plans for the their masters return. Eris Morn would call for assistance to stop the return of Crota. After the death of Sardon, Fist of Crota and failing to take control of one of Rasputin’s war bunkers on Earth, The Spawn of Crota began plans for his resurrection. They would successfully wake his soul however The Guardian would infiltrate the ritual, killing the Wakers and destroying the crystal, stopping him from re-entering the physical realm. A team of Guardians would track down and kill Omnigul, and later a six Guardian fireteam led by the Guardian would infiltrate Crota’s throne world killing Ir Yût, the Deathsinger and bringing an end to the Son of Oryx.

The Taken War
After the death of Crota’s father Oryx, the Taken King along with his forces would make there way to Sol to take revenge for the death of his son. The Guardian would take a piece of the crystal that held Crota’s Soul killing Baxx, the Gravekeeper. They would then infiltrate Crota’s Throne World, to use his essence to become Ascendant. The Deathsingers including Crota’s sisters Ir Anûk, Ir Halak, and Ir Yût, the Deathsinger who had now returned, where they holding Crota’s funeral. The Guardian successfully became Ascendant and escaped and would go on to bring an end to the Taken King. Later Malok, Pride of Oryx would arrive in the Hellmouth to attempt to seize the Osmium Throne but would be slain by a fireteam of Guardians

SIVA Crisis
The Devil Splicers would descend into the fortress to take unborn Ogre eggs. A Guardian fireteam would stop this killing the abomination they attempted to take. Following the defeat of the Devil Splicers leadership, Omnigul, Will of Crota would return and the Vanguard would task fireteams with killing her for good.

Rising from the Depths
Years later after the death of Oryx, Crota and other high ranking Hive leadership. The Hive on the Moon were left scattered and leaderless. The daughters of Crota and Omnigul Hashladûn, Besurith, Voshyr, and Kinox had now rejected the Sword Logic and couldn’t imagine a world without their King. They began plans to take control of the Hidden Swarm and resurrect Oryx. However a powerful champion known as Zulmak, Instrument of Torment became a strong candidate for leadership and a threat to the Daughters plan. Later three siblings began a conspiracy to bring an end to the Daughters, the brother Akrazul, the Severed, and the sisters Deathsinger Azavath and Malkanth, the Deceiver began a ritual where Akrazul possessed Azavath, the brother would go mad, killing his sister and many other powers champions including Zulmak before being killed by Ir Airâm, Deathsinger who has know possessed the body of Malkanth. Crota’s daughters would be greeted by their great aunt Savathûn, the Witch Queen. She would convince the daughters to take power, and construct a new fortress to stand against the servants of the Sky. She would also give them the essence of Zulmak so he could be raised as a puppet champion. The daughters would succeed in rallying the Hidden Swarm under there leadership and would construct the Scarlet Keep. However unknown to them this was a trick of the Witch Queen, as she was the one that influenced the three siblings, and placed Ir Airâm, Deathsinger in the essence of her sisters body as long as she led the Deathsinger’s choir. She manipulated the Daughters to take power, and construct the Keep so the Swarm will attract the attention of the Guardians to kill the Daughters, as the Witch Queen believed her brother's bloodline had run its course.

Shadowkeep
When Eris Morn accidentally disturbed the Lunar Pyramid, causing a curse on the Moon, awakening the Nightmares. The Daughters of Crota would use the Cryptoglyph’s to summon, command, and protect themselves against the Nightmares. After killing Hashladûn in the Scarlet Keep, and learning about the Cryptoglyph’s, Eris Morn would send the Guardian to retrieve more of them. The Guardian would enter the Hellmouth, kill Besuirth, and take the Cryptoglyph. Toland, the Shattered would later guide the The Guardian to kill Ir Airâm, Deathsinger.

Season of the Undying
With the destruction of the Sol Inherent, the Undying Mind would return and order the Sol Divisive to invade the Moon. The Vanguard would succeed in destroying the Undying Mind bringing an end to it for good.

Points of interest
The outer surface of the Hellmouth covers a wide area, including a platform overlooking the pit and a small moonbase hidden away in the rocks. Public Events, resource nodes, and patrol beacons can only be found on the surface of the Hellmouth, not within.

Trivia

 * From a design standpoint, the Hellmouth is meant to evoke feelings of scale, menace, mystery, darkness, evil, strength, militarism, and the exotic without coming across as being too alien. Its imagery is meant to invoke feelings of Medieval/Gothic architecture.
 * There is a bug were if you have a Sparrow that allows tricks you can cross the Hellmouth by going near the entrance of the Temple that leads to the Summoning Pits and The World's Grave, jumping of a angled rock near the Hellmouth, spinning at the right time, jumping off at the right time, and then Fist of Havocing once you start to fall after you jump from your Sparrow, and a whole lotta luck.

List of appearances

 * Destiny
 * The Dark Below
 * Destiny 2
 * Forsaken
 * Shadowkeep