Samuel R. Delany

When Argo, the White Goddess, orders it, Geo, the itinerant poet, and his three disparate companions journey to the island of Aptor to seize a jewel from the dark god, Hama, and return it to Argo so that she may defeat the malign forces ranged against her and the land of Leptar. But, as the four press deep into the enigmatic heart of Aptor and the easy distinctions between good and evil blur, their mission no longer seems so straightforward. For Argo already controls two of the precious stones, and possession of the third would make her power absolute. And the four friends have learned that power corrupts and absolute power corrupts absolutely...

Books like The Jewels of Aptor

Your next favorite book is out there