The Hall of Bones is located in the Imperial Palace of Carthak. It is where skeletons of ancient creatures are displayed and collected. Ozorne Tasikhe and the rulers of Carthak had many of these skeletons.
Veralidaine Sarrasri awoke the skeletons of these creatures using magic from the Graveyard Hag. The creatures acted as if alive, and could communicate with Daine. This is a higher form of necromancy, as the creatures have their full consciences back.