Elementals are a foreign concept in a lot of ways.  Creatures made up of water or air that are relatively intelligent, can be summoned or spontaneously created, and aren't just a humanoid in an element suit just seem weird.  If you ever wandered where they come from, what they can do and how the fight, give this episode a listen.

I want to specifically thank Keith Ammann and his great book The Monsters Know What They're Doing.  I cannot recommend this book highly enough.  It's an amazing read!