The Haunted Castle

A spired ancient castle stands atop a large central hill in the Haunted Realm, piercing the sky like a cluster of knives. Few adventurers have eluded the wild hunt and reached the ancient castle, and fewer still have dared trespass inside. Rumors say that ancient treasures and wondrous riches await anyone brave enough to infiltrate the castle. It's not clear where these rumors actually come from- no one knows anyone who has entered, survived, and escaped.
The Haunted Castle sits on a hill, and has a wide spiraling stone staircase leading up to its front gates on the summit. An underground tunnel runs alongside the stairs, providing arrow slits for defense. The castle has square walls about 400 ft on a side, and the central keep is 150 ft by 135 ft with two floors and a basement, situated in the center of the courtyard. In the center is a grand foyer connecting the ground and upper floors. The keep had many rooms, including a ballroom, two dining rooms, royal bedchambers, an audience hall, a chapel, and catacombs.
During 2023-05-13 Delve: Haunted Castle, pt 1 and 2023-05-20 Delve: Haunted Castle, pt 2, adventurers delved through the castle. They discovered many ghouls and wraiths, all with teardrop-shaped heads. Many skeletons were found littered about, as if a battle happened, and a hologram from the hindsight lens revealed that ghouls overran the castle's guards long ago. Ancient journals found within the castle suggested the ghouls were created in a laboratory to provide bodies for souls of the dead, but became monstrous and unpredictable. The royal bedchambers contained Ghoul King Orvald, who wielded powerful magic and spoke in an ancient tongue. The party slew him and his army of different types of ghouls.