Kalidnay was a city on Athas, ruled by the sorcerer-king Kalid-Ma. During an attempt to become a dragon, his high templar, Thakok-An sacrificed her family in the belief that it would speed his metamorphosis. As she did this, unnatural mists rolled through the city, and by dawn she was in Ravenloft, the only living inhabitant of the city, and her beloved sorcerer-king remained asleep in his crystal coffin.
The city remains on Athas, though it was reduced to an unoccupied ruin. Since then, a few brave bandit groups have used it as a base of operations, though legends of horrific undead keep most people far away from the city.