The holocron of Freedon Nadd was constructed by Freedon Nadd, who was both the first king of Onderon and a Dark Lord of the Sith, subsequent to his subjugation of the Onderonians.
Darth Bane discovered Nadd's holocron in 1000 BBY, located inside a secured room within Nadd's tomb situated on Dxun. Bane gleaned information from the holocron regarding the parasitic orbalisks that plagued the chamber (and later his own body). He also unearthed within the holocron archaic incantations for performing Sith magic. Subsequently, Bane copied the spells and gave the transcription to Darth Zannah, his apprentice.