Orcus was a god of the Underworld and punisher of broken oaths in Roman religion. As with Hades, the name of the god was also used for the Underworld itself.
Greek equivalent: Horkus
The Romans sometimes conflated Orcus with other gods such as Pluto, Hades and Dis Pater, god of the land of the dead. The name “Orcus” seems to have been given to his evil and punishing side, as the god who tormented evildoers in the afterlife.
Orcus was chiefly worshipped in rural areas; he had no official cult in the cities. This remoteness allowed for him to survive in the countryside long after the more prevalent gods had ceased to be worshipped. He survived as a folk figure into the Middle Ages, and aspects of his worship were transmuted into the wild man festivals held in rural parts of Europe through modern times. Indeed, much of what is known about the celebrations associated with Orcus come from medieval sources.