Epitaph is a campaign setting for the Fudge system. The setting does implement some variant rules and specific rules but they are fairly minor variations on the basic system.
The setting is heavily engaged with the history of the world and the cosmology. There are various geographical realms detailed as well, and power factions that span the globe. Generally speaking, the scope of the campaign is epic and the assumption is that characters will be fully developed and quite powerful during standard play.