"There they discovered the secret source of her [Amanoa's] power in the deepest tombs of the palace: Freedon Nadd's sarcophagus, filled with the dark power of the ancient Sith warrior. Confronted by the light side strength of Jedi Master Arca Jeth, Freedon Nadd withdrew his strength from Amanoa, and she collapsed, lifeless, to the floor." -- Dark Side Sourcebook
"Nadd managed to preserve his spirit, locked away in the tomb with the Sith artifacts he work to obtain. His spirit then inhabited the bodies of the leaders of Onderon, including King Ommin." -- The Complete Star Wars Encyclopedia
"Upon his death, his tomb became a focus of dark side energy, which Galia’s ancestors used through the centuries." -- Tales of the Jedi Companion