In the last few weeks, I've been further developing the world of my book. It's a fictional world which resembles a mix between Pre-Middle Ages (Late Roman Empire) and the Middle/Late Pleistocene (though there's no specific time period in regards to real world chronology). There's many classic fantasy races/creatures, but they appear more "realistic" than in classic depictions. For example, griffins are a type of quadrupedal bird (with hair-like feathers, like a kiwi), and various beastmen (minotaurs, satyrs, and centaurs) are evolved Chalicotheres. Evolution doesn't work exactly the same as in the real world (some races are bestowed with magic abilities), but I'm trying not to make anything to ridiculous. The problem I've run into now is how to incorporate nature spirits (nymphs) into the story. They're spirits of the water and plants, but I don't know if they fit in with the "semi-realistic" world I've set up (there's no way for them to evolve). Do you reading this think that it would mess it up if I included them?