Castle Ravenloft was the seat of power of the lord of Zarovich Valley, originally built at the request of Count Strahd von Zarovich. It was located atop a large spire of rock overlooking the Village of Barovia below, where the von Zarovich ancestral home was built. The construction of Castle Ravenloft took many years, under construction of the wizard Orlev ben Khazan and a cadre of artisans and workers loyal to his family.
Named after Strahd's mother Ravenovia van Roeyen, it was made white and grey stone; at Strahd's request, the castle originally shimmered in the daylight, intending to display the nobility of von Zarovich rule to all who gazed upon it. Though undoubtedly a masterwork of stonecraft, the castle was also built to be a defensive fortress. Two reach the keep, an entrant had to pass two turrets of stone to a cliffside, where a 50-foot drawbridge acted as the only entrance to the castle; below the drawbridge was a 1000-foot drop to the cliffs below. Once across the bridge, a portcullis led to the only tunnel inside, as keep's protective walls that enclosed the courtyard were 90-feet high.
After its completion, Strahd invited his remaining family to castle, and planned to rule with them at his side for the rest of his days. However, he grew covetous of his brother Sergei von Zarovich's bride-to-be Tatyana Federovna, and killed his brother in the Wedding That Never Was. Strahd made a pact with Vampyr that changed the landscape of his home forever, trapping the valley in choking thick mist. For centuries, Strahd ruled as the Vampire Lord of Barovia, and his castle blackened.
Besides Strahd himself, Castle Ravenloft was inhabited by several of his undead servants, thralls, and occasional prisoners. They used the castle as a base of transport; a magical brazier in the catacombs allowed for travel throughout Barovia by casting a gemstone into a magical fire, opening a Portal to a specified area. The destinations could be changed by Count Strahd at will, but were generally indicated in a poem form beneath the brazier, such as:
Violet to where coffins wait
Indigo to bridge's gate
Blue to view the cold knight's rage
Green to glimpse a bygone age
Yellow to the morning's tomb
Orange to dark magic's womb
Red to the high castle spire
Cast a stone into the fire!