The gods of this world can generally be classified into one of five categories. These categories, however, are not hard and fast distinctions. The difference between any two adjacent categories can be seen as highly subjective, with one god being included among a higher category while another god of roughly equal power is relegated to the lower.
Elder Gods. The elder gods created the world. Then, for whatever reason, they largely abandoned it. Elder gods are supremely powerful, but never seen. Most mortals have only heard about these deities in passing, dismissing any mention of them out of hand. They are the "gods of the gods," some might say.
Greater Gods. These are the most powerful of the gods who are known to mortals. On a whim, they can raze entire continents and boil whole oceans. The whole world over, these gods are worshiped by those who love and fear them. In response, these gods larger keep to themselves, having long since tired of daily interactions with mortals.
Lesser Gods. These gods aspire to become greater, overthrowing the greater gods who are holding them down. To achieve this, the gods and their clergy actively pursue ever greater numbers of worshipers. These are the gods who are most likely to use entire nations as pawns in the eternal struggle to overthrow their betters.
Exarchs. Relegated to relatively small numbers of worshippers, most exarchs are content to serve a greater or lesser god. Many exarchs who are well loved in one area of the world may have never even been heard of elsewhere, another exarch controlling the same domain and being worshiped there in their stead. That is not to say that exarchs lack ambition; most are simply smart enough to realize that such ambition must be tempered with patience if they are to survive.
Demi-Gods. Sometimes seen as naught more than powerful men, demi-gods have the smallest spark of divinity. They rarely have worshippers, instead contenting themselves with the devotion of those who love or fear them personally. For these beings, great and often terrible deeds are the order of the day, single-handedly slaying entire armies to instill fear or fighting ancient dragons to prove their worth.