The Gravestone is a key item in Drakan: The Ancients' Gates. It is an ancient artifact with incredible necromantic powers. The ancient necromancer, Khossa Vole, survived an earlier attempt on his life and found the Gravestone as a way to increase his power. He fashioned a void world wherein he could raise an army of the dead and lay siege to the city of Surdana.
Rynn flew to Vole's tower and entered the void world. There, she destroyed Vole's physical body, enabling her to destroy his spectre as well. She recovered the Gravestone and the void world collapsed around her. She took the stone to Jade where the sorceress could keep it safe and out of the hands of the likes of Vole.
Drakan: Order of the Flame - Drakan: The Ancients' Gates