Herentor

Herentor is said to be the most powerful wizard who ever lived on Eavaros. She was an elven woman, one of the first Fatemakers who ended The Calamity. In the 2020 flashback, Braggum's player played her as an Intelligence-20 wizard.

At the last battle she turned Mol'maroch The Nethershaper to obsidian. Then, using the soul of Mystra, she cast Planetary Schism, Global Suggestion and Cosmic Lock, which sealed the southern continent away from the north (Herentor's Wall). The veil, a 10th-level working, hid the south even from other planes and erased all memory of it; it was destroyed in the final months of The Skyfire (1019 PC). The working tore her apart, Pandemonium leaked in, and she and her ring vanished from the plane. The Shrine of the Last in Fort Obsidian marks "where Herentor cast those big ass spells", and she appears on the tapestries in the Scale Keep with an open spellbook.

In campaign 4 the party learned from the ruins of Rillachor beneath Sandwater Slough that its astral elves had pierced "Herentor's spell". They also learned that the fall of Herentor's veil, in 1019 PC, set their ancient terraforming running out of control as The Great Evaporation, the desertification of The Restless Expanse and the south.

The Seven Journals of Mechanus call it "Herentor's lock", date its fall to "T-26", and say the southern continents were severed from the wider world while it stood.