The Spellplague was a disaster that struck Realmspace on the 29th of the Claw of Storms in the Year of Blue Fire (353 NR, 1385 DR), set in motion by the assassination of Mystra by Cyric, acting on Shar’s instructions. With the goddess’s death, the Weave, the universal structure of arcane forces, was destroyed. For a decade, called the Wailing Years, arcane magic ceased to function and the planet of Toril was transformed.
The storm began over the Mhair Jungles west of Halruaa and quickly grew to a massive size, with blue flames visible in the sky. It laid waste to Halruaa due to the heavy wild magic activity in the area, and Sespech, the Golden Plains and the Nagalands were transformed into an unpredictable and surreal place, dubbed the Plaguewrought Lands. Almost every part of Faerûn was affected by the Spellplague. Some areas were destroyed entirely, while others were created anew. Thousands of mages were either destroyed or went insane by the collapse of the Weave. In Cormyr, a third of the War Wizards were either killed or driven mad. Those who survived were forced to learn martial combat when they found that magic had disappeared.
The Spellplague affected the landscape, making the ground rumble and heave up and down like the surface of the sea. Curtains of blue flame swept the landscape, reshaping the land by cutting crevasses or lifting and sculpting the plain into hills and ridges. Shards of earth wrenched themselves free and became earthmotes. Waves of azure fires appeared everywhere, killing whatever they touched. Rifts opened in the Underdark beneath the Sea of Fallen Stars, causing the level of water to drop, cutting many ports off from their livelihood.
While small, almost imperceptible parts of Abeir and Toril had been switching places since the Time of Troubles, it was the Spellplague that caused large-scale transitions to occur. Toril’s Maztica swapped with Abeir’s continent of Laerakond, which became known as ‘Returned Abeir’. Mulhorand was utterly destroyed, while Unther was squashed beneath a fragment of the dragonborn nation of Tymanchebar, which became the realm of Tymanther. Chult became a large island when most of the Chultan Peninsula was cut off from the mainland, while Evermeet was pushed into the Feywild.
Most permanent magic items, such as artifacts, were left intact at the end of the Spellplague, but charged magical items were either destroyed, warped, or simply ceased to function. Items with dormant magical qualities, which were manually activated, were largely unaffected by the Spellplague.
These disasters set the stage for an era of political upheaval, particularly in states that relied heavily on arcane magic to maintain their power. Coups, invasions, and uprisings swept Faerûn. Technology and divine magic became much more popular to fill the void left by the failure of arcane magic, and the deities of knowledge and invention saw their churches swell.
Among the gods, Mystra’s assassination had a number of repercussions. Her home plane, Dweomerheart, dissolved, killing Savras, the god of divination. Asmodeus seized Azuth, the god of spells, and stole his divine essence to become a god himself. Lathander transformed into his ancient guise of Amaunator, the god of the sun and law. Cyric was tried by a conclave formed of Amauntor, Sune and Tyr. They found him guilty of Mystra’s murder and sentenced him to imprisonment in the Supreme Throne.
By the Year of Silent Death (363 NR, 1395 DR), arcane magic had emerged again as a sort of natural force without a Weave or divine control. Many arcanists struggled to learn how to master magic again without the Weave, and many failed to do so.
Plaguelands are areas or regions where the effects of the Spellplague still continue. Creatures that venture too close to a plagueland might gain a spellscar. A spellscar might leave no visible mark, or it could leave a marking in blue flame on the skin (or perhaps worse). It is possible to master a spellscar and draw arcane powers from it, but these are unpredictable at best.
Creatures consumed by the original wave of the Spellplague are called plaguechanged. The initial plague was so virulent and the changes it wrought so extreme that most were simply killed by it. Those that did survive were twisted into monsters in body and mind, driven insane by their dreadful metamorphosis. Even the least of them display potent abilities. Fortunately, few of their descendants have survived, as their transformation also made it difficult, if not impossible, for most of them to reproduce. The Chasm in Neverwinter is peculiar for the seemingly endless flow of plaguechanged monsters that seem to rise up out of it, even a century after the Spellplague.