Sword Coast Gazetteer

From the back of the book:

Doomed Forgotten Realms: Sword Coast Gazetteer is a reimagining of the Forgotten Realms in which every worst possible outcome became a reality. The demons claimed the Underdark, Baldur’s Gate was dragged into hell, Auril froze over all of Icewind Dale, and Tiamat was summoned to rain down terror. In the Doomed Forgotten Realms, all the adventuring heroes failed, slain in their conquest—or no one ever answered the call for aid. However, there is always the faintest glimmer of hope for good to emerge victorious at the end of the day.