The Calamity

The Calamity was the war fought by the Prime Deities against the Betrayer Gods at the end of the Age of Arcanum. Lasting for at least a century, it ended the Age of Arcanum and resulted in the Divergence, in which the Betrayer Gods were all banished from Exandria, the Divine Gate was constructed, and the Prime Deities permanently left Exandria as well.

Post-Calamity historians estimate only one-third of Exandria's population survived. All civilizations aside from Vasselheim were destroyed and, with it, most records, technology, and magical research. Historical knowledge of the Calamity and the Age of Arcanum is limited as a result. The war also left extensive geographical changes to Exandria, including the desertification of Marquet, the destruction of the land bridge connecting Tal'Dorei and Wildemount, the corruption of the Miskath Strand into Blightshore, and transformation of rock in the Alabaster Sierras into whitestone.

Timeframe and dates
The Calamity occurred at the end of the Age of Arcanum and ended with the Divergence. Occasionally, the Calamity is described as a separate epoch from the Age of Arcanum, but it is more consistently described as occurring at the end of the Age of Arcanum and ending it. Though most often referred to as a singular war, the Calamity is occasionally defined as multiple but collective wars between the gods and the resulting cataclysms.

In the era following the Calamity, the calendar of Exandria uses the year notation of Post-Divergence (PD), with the Divergence happening at about year 0 PD; Campaign One starts in 810 PD, which dates the Divergence, and thus the end of the Calamity, to 810 years before the events of. It is unclear exactly when the Calamity started or how long it lasted, but it is suggested to have lasted for more than 150 years. References to the length of the Calamity include:
 * Vasselheim is described as "having endured a terrible war that wiped out most of civilization more than a thousand years ago" in 812 PD, suggesting that the Calamity started over 188 years before the Divergence.
 * The kingdom of Uthtor was destroyed in the Calamity "nearly a millennia [sic]" before 812 PD.
 * Torog's incursion into the Pallid Grove during the Calamity is described as occurring "nearly a millennium" before 835 PD, which would be around 165 years before the Divergence.
 * The wilderness that spanned what is now the Greying Wildlands burned with arcane fires set during the war "for over a hundred years" before Molaesmyr was founded after the Divergence.
 * Halas Lutagran said that the destruction of Aeor during the Calamity occurred before he was born, though he knew stories of it growing up, and twice indicated that the Calamity was ongoing at the time he became trapped in a gem. He was described as appearing in his mid-50s at the time he became trapped, but time inside in his extraplanar home moves slower at a rate of one hour for every day in Exandria.

Background
The separation of the gods into factions arose during the Founding. The Primordials that lived on Exandria before creation destroyed many of the peoples created by the gods. Those that sought to protect the new peoples of Exandria in fighting the Primordials became known as the Prime Deities; others, siding with the Primordials, fought against them and became known as the Betrayer Gods. The Prime Deities ultimately defeated the Primordials and banished the Betrayer Gods from the Material Plane.

In the following era, the Age of Arcanum, a mage woman developed the Ritual of Seeding, destroying the previous god of death and ascending in his place as the Raven Queen. This inspired Vespin Chloras, who turned to the Betrayer Gods to acquire similar power. He released the Betrayer Gods back onto the Material Plane.

The Betrayer Gods surreptitiously founded their own kingdom Ghor Dranas located in Xhorhas in eastern Wildemount. From there, they quietly spread their influence among mortals and consolidated their power. Ghor Veles in the Miskath Strand served as an arcane vault and research facility for the Betrayer Gods before the war.

Assault on Vasselheim
In time, the Betrayer Gods and their followers launched a surprise attack on Vasselheim, making the presence of the Betrayer Gods on Exandria known. The attack destroyed a significant amount of the city, but the city survived with aid from the Prime Deities. After a battle between the gods and their followers that lasted for twenty days, the Betrayer Gods were ultimately forced to retreat. This, however, mobilized Exandria and the Prime Deities to war against the Betrayer Gods and their followers.

Preparations for war
The revelation that many mortals fell to the influence of the Betrayer Gods shattered trust across various peoples, who no longer knew who to count as an ally. Humans, who trusted only themselves, forged artifacts to be wielded by specific heroes. Many dwarvish peoples became isolationist; they dug deeper underneath their mountain homes and animated constructs to protect themselves. Elves focused their effort on creating new, stronger, more destructive magic. Deities of both factions, archmages, and others crafted legendary artifacts during this period, called now the Vestiges of Divergence.

Some peoples attempted to escape the imminent war before it began. Followers of Zehir slaughtered the people in the Vault of Shumas and locked it off, placing it under the care of an undead caregiver. An adventure hook in the Tal'Dorei Campaign Setting, "A Dormant Threat", similarly describes the seers of the serpentfolk empire of Vos'sykriss (now Visa Isle) as having foreseen the Calamity; to survive the coming war, they created a magical stasis field under their city, suspending their strongest and most powerful so that they may rebuild afterwards. The Qoniira Tetrarchy in southern Tal'Dorei chose not to fight and withdrew from the world. As a result, a magic that post-Divergence Qoniirans cannot explain called the Gift closed the Riftenmist Jungle around the city of Niirdal-Poc to protect it. Similarly, the fallen Court of Ullusa, who would later become the elves of Syngorn, fled to the Feywild and did not return until a generation later. Almost all elven civilizations disappeared from Exandria to escape.

Approximated chronology
The precise time line of the Calamity is unclear, particularly because the surviving peoples of Exandria do not know much about the history of the war. Some events can be roughly ordered chronologically:
 * Lolth possibly cursed Mirescar.
 * Lolth, one of the first casualties of the war, was impaled by Kord's thunderspear and banished to the Abyss before her soldiers fought any battle, driving the drow into the Underdark.
 * Early in the Calamity, a civilization in Marquet collapsed as a result of an internal war that turned the verdant landscape into ash and desert. This civilization is possibly Cael Morrow, over which Ank'Harel was built.
 * The kingdom of Uthtor was destroyed.
 * Torog and his followers bypassed the protective illusions of a reclusive society of elves who worshiped Sehanine and tunneled beneath a woodland atop a plateau in the Cyrios Mountains in Wildemount, ultimately creating the Pallid Grove.
 * Moradin and Sehanine built the King's Cage in Bazzoxan in Xhorhas as a trap for Torog. It appeared to be a temple to Torog, but it was a fane that would allow them to banish him. Pelor and Sarenrae drew Torog above ground, defeated him, and banished him to a portion of the Far Realm that borders the Underdark. Torog's tears burned tunnels through Exandria, and his followers fled into them.
 * Sarenrae, as she believed even the corrupt can be redeemed, was deceived and betrayed by Asmodeus, who killed most or all of her worshipers in a single stroke.
 * The original Cerberus Assembly tore Desirat, Asmodeus' phoenix mount, from her master and bound her underneath Mount Mentiri in Wildemount.
 * Avandra defeated Asmodeus by tricking his armies into fighting each other.
 * In a battle late in the Calamity, and after a multiple clashes between the two gods over the course of the war, Melora and her Free Children defeated Bane and his goblinoid legions on the Beynsfal Plateaus in what would become known as Gwessar, leaving his armor scattered across the region and freeing the goblinkin. The battle left the region ashen, no longer able to support plant life.
 * Using the Rites of Prime Banishment, the Prime Deities banished Tharizdun. Moradin crafted four Prime Trammels on the Core Anvil. Ioun baited Tharizdun to her central temple in northern Gwessar (in what is now Whitestone), resulting her near-destruction and causing her temple to sink underground. With Avandra's blessing, a furious Pelor embedded the trammels into Tharizdun, who fled to Gatshadow Mountain. Pelor gave chase and banished Tharizdun.
 * At the location where Tharizdun wounded Ioun, Pelor planted the Sun Tree.
 * Kord created the Stormlord's Heart, which would allow his champions to enter Lolth's home in the Abyss, and hid it in Bazzoxan in case the Prime Deities would be defeated in the final battles.
 * The final battles occurred in what is now the Barbed Fields, ultimately razing Ghor Dranas. These battles also sundered the mountain range dividing Wynandir, creating the Brokenveil Bluffs and separating the range into the Ashkeeper Peaks and the Dunrock Mountains.
 * In the Barbed Fields, Melora planted the Arbor Exemplar.
 * With all the Betrayer Gods banished, Bahamut and Erathis suggested that the Prime Deities themselves also leave Exandria. The gods erected the Divine Gate behind them, ending the Calamity and the Age of Arcanum.

Events with unknown chronology
Other events during the Calamity that do not have clear a place in the overall chronology:
 * All deities momentarily struck an armistice to destroy the flying city-state of Aeor, a mageocracy which had developed weapons to kill gods. Aeor disappeared into the north and crashed in Eiselcross.
 * At least fifty years after the fall of Aeor, other flying cities in Wildemount, including Zemniaz in the Zemni Fields and Kethesk in the Dreemoth Ravine, also crashed.
 * Clemain Astural looked into the Far Realm for the power to end the war. He received such power but lost his sanity under the influence of the Sightless One. He sowed chaos across southeastern Gwessar before he was killed.
 * A Luxon beacon was found by the drow in the Underdark.
 * Gruumsh vengefully devastated Marquet, creating the Rumedam Desert. A great hero, whose tale survives only in fragments, sacrificed himself to save the continent from complete destruction.
 * Corellon battled Gruumsh and took out his eye at the hill now known as the Throne of the Archeart, also known as the Fist of the Ruiner.  Afterward, elves of northern Wildemount begged for aid from Corellon. Corellon, temporarily defeaned from their battle with Gruumsh, did not answer, so the elves fled to the Feywild.
 * An alleged temple on the northern shore of the Ounterloch sank into water due to earthquakes caused by the fighting.
 * A battle in northern Wildemount turned the northern Veluthil Forest into a wintry desert, creating the Crystalsands Tundra.
 * The southern Veluthil Forest was set ablaze and burned for the remainder of the Calamity.
 * Xalicas, Corellon's right hand, was horrifically injured in a battle in what is now the Greying Wildlands. She did not have the strength to move from where she lay for over a century.
 * The Raven Queen's angels saved her from a near-fatal encounter with Tharizdun, but all the angels were consumed by Tharizdun in the process.
 * Zehir ambushed and killed many follower's of Melora, and her anguished fury created the poisonous wilderness of the Lushgut Forest.
 * A servant of Torog fell in battle in Wildemount, poisoning the marshes now known as the Saltwallow Bog.
 * One of the bloodiest battles of the Calamity took place at what is now Bladegarden, leaving behind a vast amount of weaponry.
 * Fighting took place at Incanter's Rest in Wildemount. Post-Calamity historians are unsure if multiple battles or the largest battle on the continent occurred there.
 * The land bridge connecting Wildemount and Gwessar was shattered, creating the Shearing Channel.
 * Siff Duthar, a necromancer in the Marrow Valley, conducted experiments on refugees in an effort to bind his soul and survive teh war. He was ultimately successful and became an allip.
 * Halas traps himself inside of a gem after someone sabotages his components for his experiments to prolong his natural life.
 * Orcus gave two of his horns to a champion. This champion was killed and their body completely destroyed, but the horns remained and were locked away.

Society during the Calamity
In general, the inability of the Betrayer Gods to work together allowed them to be defeated, though for a brief period there was unity between the Demon Princes for the purposes of fighting the Prime Deities. Abyssal anchors, which can tear holes through the barriers between the Abyss and the Prime Material Plane, were used during the Calamity to allow demon generals to invade various places in Exandria. Mages and followers of the Betrayer Gods used gloomstalkers as mounts during the war.

The banishment of Lolth early in the war left the drow leaderless and unable to communicate with her. As a result, they were driven from the surface into the Underdark, where they rebuilt. Once there, their nobility began to fall under the influence of Tharizdun; others abandoned worship of Lolth after a Luxon beacon was found during the war. Over the years, those who remained loyal to Lolth discovered bloods of her blood and drank it, becoming half-spider hybrids called driders.

Though most elven societies fled the plane before the war, a handful remained on Exandria, including the Horselords of Laphitas (see: Associated origins and creation myths). The elves in northern Wildemount remained on the plane until after Corellon was temporarily deafened in their battle with Gruumsh, leaving their pleas for protection unheard; these elves encased their civilization in ice before fleeing the plane. The Sehanine-worshiping society living in what became the Pallid Grove were thought destroyed by Torog after he invaded their home and kidnapped many of them to be tortured, but many survived by living underground under the protection of Sehanine's blessings, becoming pallid elves. A wandering colony of elves fled the Calamity, eventually becoming the Orroyen tribes of the Rifenmist Peninsula.

Kuul'tevir, the lizardfolk of Tal'Dorei, used "corrupting magic" to preserve their grand cities and prospered during the Calamity through the magic of demons and evil gods. However, they turned against each other in their pursuit to do anything to survive the war, ultimately destroying their societies themselves.

In the Ashkeeper Peaks, the dwarven clan of Grimgol was almost wiped out; the survivors burrowed deep and collapsed the established tunnels to buffer against the wars above, and so began centuries of isolation. Other dwarven strongholds in the Ebonglass Massif, including Xagonstar, were completely destroyed.

The core spawn, concentrated in Blightshore, were awakened by the actions of the Betrayer Gods and their followers during the war.

Associated origins and creation myths
Prior to the Calamity, Bane bent most of the dranassar of Wildemount to his will. Those who resisted were transformed into the first goblinkin to serve in his armies during the Calamity, with each race of goblinkin formed to fulfill a specific purpose. As the war continued and more soldiers were needed, loyal dranassar were transformed as well. This left all goblinkin burdened with the Curse of Strife.

The Raven Queen's angels saved the Raven Queen from Tharizdun, but they were all consumed into his infinite void in the process. Though they were believed destroyed, they were freed when Tharizdun was defeated near the end of the Calamity. They returned as the mortal kenku, having lost their divine gifts, their wings, and memories of their existence as the Raven's Queen's angels. Cursed by Tharizdun's curse of oblivion, they became small creatures who could only speak in mimicry.

Though many elvish societies fled to the Feywild, the Horselords of Laphithas stayed on Exandria to fight alongside Corellon against Gruumsh at the Throne of the Archheart in Gwessar. Centaurs are said to have been created when the Horselords were slain by a burst of magic when Corellon stabbed Gruumsh's eye, merging them with their horses; as a reward and gesture of mercy, Corellon revived the elves as centaurs. Orcs are believed to have been accidentally created in the same battle from the elves who were seared and changed by Gruumsh's blood. Each story "conflicts somewhat" with the other, and it is described as possible that neither is accurate or both are simultaneously true. Further, some sources say that Wildemount's first half-orcs were born in the war's final days out of a union between humans and orcish traitors, though others say half-orcs did not exist in Exandria until after the Calamity.

Catfolk generally agree they were once normal animals who were transformation by magic. When this occurred or what the source was has multiple theories, including that it was the magic unleashed during the Calamity. Similarly, gnolls were created when a demon prince arrived on Exandria to fight in the Calamity. A pack of wild dogs were caught in the surrounding nimbus, which turned the dogs into gnolls.

A "particularly pervasive" origin myth for the dragonblood say that they were created by Tiamat and Bahamut during the Calamity as soldiers, and that these soldiers eventually earned their freedom as the dragonblood.

The Sehanine-worshiping elves whose home was transformed into the Pallid Grove retreated underground, beneath the Grove, and became pallid elves. Those drow who remained loyal to Lolth discovered bloods of her blood and drank it, becoming half-spider hybrids called driders.

The Divergence
After the defeat of Ghor Dranas and the banishment of the Betrayer Gods, the Prime Deities knew that the Betrayer Gods could return again and sought to prevent a third divine war. In the hopes of sealing the Betrayer Gods away permanently and feeling that their own involvement bore responsibility for the vast destruction, the Prime Deities self-imposed an exile from Exandria and returned to their own realms. At the suggestion of Bahamut and Erathis, they erected the Divine Gate, preventing any god from physically crossing into the Material Plane. This event, known primarily as the Divergence, ended the Calamity and with it, the Age of Arcanum. The age following is known as post-Divergence or post-Calamity.

Aftermath
The Calamity resulted in significant physical changes for Exandria. The war destroyed most existing civilizations and cities, leaving only Vasselheim as a surviving bastion, and historians in the post-Divergence estimate that only one-third of the planet's population at the time survived.

Significant amounts of magical research and technology was lost in the war. This included original sources of brumestone, study in dunamancy, and the creation of ensouled constructs such as aeormatons. Many of the Vestiges of Divergence and Arms of the Betrayers were lost during the Calamity, including Fethras, all but one Grimoire Infinitus spellbook, and the Blade of Broken Mirrors.

Generally, most pre-Divergence history was lost in the war, leaving post-Divergence understanding of it full of gaps. This included history on pre-Calamity human civilization in what would become Gwessar was lost as their records were destroyed and, unlike the dwarves and elves, their shorter lifespans left them without individuals who remembered the world as it used to be. Though most records were lost as a result of the widespread destruction, some were destroyed purposefully to prevent others from recreating the tools from the Age of Arcanum that led to a was as destructive as the Calamity. As a result of both, little history is known about the Calamity and the Age of Arcanum.

Vasselheim was the only civilization to survive the war. Due to the events of the Age of Arcanum and the resulting Calamity, arcane magic became viewed with suspicion in the city.

Many societies were annihilated. Wildemount's flying city-states Aeor, Zemniaz, and Kethesk were destroyed, and none of Exandria's flying cities were known to have survived. Though the cultures of Zemniaz and Kethesk endured through survivors who lived in the Zemni Fields and who founded Draconica respectively, Aeorian society completely vanished, locked away in the remote depths of Eiselcross. A group of drow who worshiped a pre-Founding being called the Luxon instead of Lolth climbed out of the underdark. Led by Den Kryn and Leylas Kryn, who was present when the first Luxon beacon was found, they founded the first post-Calamity society in Xhorhas, the Kryn Dynasty, in the new city of Rosohna built on the ruins of Ghor Dranas. Uthodurn was followed shortly after, founded soon after 35 PD in northern Wildemount. The dranassar were almost entirely destroyed, and the very few who survived into the post-Divergence live disguised and in hiding. Few remained in Gwessar as the remnants of Bane's invading armies, but most can be found in their home continent Wildemount.

Of the peoples in what would become Gwessar, the dwarves are described as having "best weathered" the war, and the surviving families of the kingdom of Uthtor founded Kraghammer underneath the Cliffkeep Mountains. They were the first peoples of the continent to resuming mining operations. The elvish peoples of Gwessar returned from the Feywild a generation later. Led by Yenlara Alderwreath, they settled in the Verdant Expanse and built a Syngorn, which in turn named the continent Gwessar. The centaur tribes of the Dividing Plains, who are said to have been created from elves who remained on Exandria to fight, hold a grudge against Syngorn for fleeing during the Calamity. Halflings settled the Dividing Planes and the foothills of the Cliffkeep Mountains. Humans would not return to Gwessar to establish a new society for centuries.

In Marquet, portions a civilations in Marquet survived the war, and the city of Ank'Harel was founded on top of it as among the first societies to rebuild afterward. A society of orcish people who survived Gruumsh's destruction of Marquet founded a city on the continent known for its "mathematically immaculate architecture".

Effect on worship
The Divine Gate ensured that the gods could no longer cross onto the Material Plane, reducing their ability to enact their will on Exandria to granting power to their clerics and followers.

Because Sarenrae's trusting nature is what led to her betrayal and destruction of her followers by Bane, many priests erased her name from history. Her name, title, and worship fell into obscurity for centuries, only to begin a revival eight hundred years later. Similarly, Ioun was injured in battle with Tharizdun and her sorrow caused her central temple to sink underground; her public worship was broken and her presence in Vasselheim reduced, many of her followers were killed during the Calamity and hunted by followers of her ancient enemies afterward, and she faded into obscurity. Over eight centuries later, Ioun was still recovering from her wound. The Cobalt Soul was founded in Wildemount shortly after the Calamity to continue her work on Exandria.

Of the Betrayer Gods, most of Zehir's followers were also killed during the war with the remainder either in self-induced stasis or hunted for sport by followers of Lolth and Torog. Lolth lost influence in Wildemount as the drow rejected her to worship the Luxon instead; she took this as a personal betrayal.

Geographical changes
Similarly, the last battle sent strong waves of magical force throughout Exandria. This collapsed most of the Crystalfen Caverns, unintentionally causing the fall of the aberration civilization centered at Salar. A shift in ley energy after the Calamity accelerated growth that created the Verdant Expanse, a place untouched by the Betrayer Gods, and filled the groves with stranded fey and displaced aberrations. The continents of Wildemount and Gwessar became completely separated from one another when the land bridge between them collapsed, leaving the treacherous Shearing Channel.

Xhorhas, once densely forested, became a blasted wasteland. the Barbed Fields are a treacherous land pocked with sinkholes and tar pits. The once-tranquil coastal paradise of the Miskath Strand was defiled by the Betrayer Gods and became the dramatically transformed Blightshore. The final battles created tidal surges in the Lucidian Ocean, flooding the Swavain Islands and the Menagerie Coast. When the waters receded, most civilization there had been swept away, and jungles reclaimed the land. These battles also sundered the mountain range dividing Wynandir, creating the Brokenveil Bluffs and separating the range into the Ashkeeper Peaks and the Dunrock Mountains. This may be when the mountains the dwarven clan of Grimgol had called home were destroyed. Less than a century before the war ended, an extremely slow-burning arcane forest fire started in what later became the Greying Wildlands, and was not extinguished until after the Calamity ended.

The battle between Pelor and Tharizdun in the Alabaster Sierras raised the mountains upward, creating the valley that would become the Parchwood Timberlands. The mountains became infused with residuum, remnants of arcane energy, and creating the easily enchanted and valuable whitestone of the Sierras. This also resulted in the woodland becoming filled with monsters. Toward the end of the war, the site of Melora's final battle with Bane in the Beynsfal Plateaus was reduced to ash, and plants wouldn't grow there ever again.

Marquet was previously a verdant landscape before the Calamity, and it was reduced to ash and desert between an internal war and Gruumsh striking the continent.

Known survivors
Individuals who endured into the post-Divergence era through undeath, such as Siff Duthar, are not included. Those listed either lived on Exandria during the Calamity or specifically fled the plane ahead of the war.
 * Abrianna Mirimm, drow living in the Underdark who worships the Luxon.
 * Brashaar, human mage and architect at Aeor when it fell. She was preserved by a magical stasis bubble, but she remains frozen in time within.
 * Desirat, phoenix mount of Asmodeus. She was captured by mages during the war and imprisoned underneath Mount Mentiri, where she remains trapped.
 * Devexian, aeormaton. His power crystal was destroyed in Aeor's crash, but he was revived when the Mighty Nein replaced it in 836 PD.
 * Galdric, wolf companion of the Raven Queen's champion Purvan Suul. He slept inside the Raven's Slumber amulet for centuries.
 * Halas Lutagran, human archmage from Zeidel. He accidentally trapped his soul inside a gem, which remained in his extraplanar home for centuries.
 * Jourrael, drow assassin for Lolth. For lack of a way to kill her, she was split into three pieces, which were sealed in secret locations across Wildemount.
 * The Laughing Hand, champion of Torog. For lack of a way to kill him, he was sealed inside the King's Cage underneath Bazzoxan.
 * Leylas Kryn, drow living in the Underdark who worships the Luxon. She was present when the first Luxon beacon was found and founded the Kryn Dynasty in the post-Calamity.
 * Quajath, scout for Torog. He was thought killed during the final battles, but he instead escaped by abandoning most of his wounded body. As a fragment, he burrowed into the earth and slept underneath Eiselcross, recovering and regrowing. When he later attempted to return to the surface, he became trapped in the ice of the continent.
 * Somnovem, archmages of Aeor, and others of the Cognouza ward. As the gods approached to smite Aeor, the Somnovem teleported the entirety of Cognouza into the Astral Sea to escape. Shortly after, a psychic wind merged their consciousnesses into one.
 * Uk'otoa, leviathan created by Zehir and one of his greatest warriors during the war. In Zehir's absence, masterless and purposeless, Uk'ota eventually began to see himself as near-divine and became a patron of the Ki'Nau people.
 * Xalicas, solar and right hand of Corellon. Horrifically injured in battle in what is now the Greying Wildlands, she did not have the strength to move from where she fell for over a century.