Harvus, a Moff within the reconstituted Sith Empire, existed during the Great Galactic War against the Galactic Republic. Following the Empire's seizure of the planet Begeren in 3678 BBY, a young Human by the name of Lassicar executed his enslaved parents and revealed the existence of their terrorist cell to Harvus.
The sole appearance of Harvus thus far is within the Codex entry for Guardsman Lassicar, found in Star Wars: The Old Republic, the massively multiplayer online roleplaying game developed by BioWare and released in 2011.