Within the context of the Forgotten Realms, raw magic is characterized as difficult for mortals to access safely. The Weave works to protect the world from the dangers of unrefined magic while giving the ability to cast spells to magic users. Destroying the Weave results in widespread destruction. Reckless use of magic can also damage the Weave, creating areas of dead or wild magic where normal spellcasting doesn't work. In ancient Netheril, "Spellcasters are arcanists and do not memorise spells – they merely pluck them out of the weave." The weave is present in everything and, until the events leading up to the Spellplague, was part of the goddess Mystra's body, who actively willed its effects. As described in earlier editions, when spellcasters would abuse magic, Mystra could cut off the spellcaster's ability to use magic.
History
In the history of Faerûn, the Weave has been destroyed twice. Because the Weave is inextricably bound to the deity in charge of maintaining it, killing this deity also destroys the Weave. The first time this occurred was when an archwizard attempted to rob the goddess Mystryl of her power. When he could not handle the power, the Weave became destabilized and Mystryl chose to sacrifice herself, which briefly stopped magic until Mystryl was reincarnated as Mystra.:47 The second time this occurred was when the goddess Mystra was assassinated in 1385 DR. The Weave collapsed and initiated the Spellplague, leading to several long-standing effects:
Realms that had been separated from Toril, the world of Faerûn, returned after millions of years of separation, including landforms from Abeir fusing with Toril and the Feywild coming closer in proximity.
A large part of Faerûn fell into the Underdark, draining the Sea of Fallen Stars and forming the Underchasm.
Creatures touched by the Spellplague were hideously mutated into powerful monsters or spellscarred beings with special abilities.
Some deities were slain.
Most magical portals were rendered inert or malfunctioning.
Items that permanently store magic and divine magic remained unchanged.
The goddess Shar lost control of the Shadow Weave.
