This page presents a good example. When I first conceived of The Cauldron the main characters were a human woman and a male elf. As time went on I became less interested in playing with standard faerie creatures. The elves became something else, another species of primate, a species that evolved from older stock, older even than monkeys.
The lost continent of Lemuria got its name, I’m told, from someone’s theory that the lemurs scattered around the Pacific must have evolved in a central place – Lemuria, land of the lemurs. So I thought, what if the Lemurians hadn’t been an advanced human society? What if they hadn’t been human at all?