"Well, there's different races between the species," Casey said. It was obvious, but the question made them realize perhaps Jack didn't understand. They were trying very hard not to think of it in a regular frame of reference. Everyone should know this. This was more than common knowledge, this simply was. They paused, breathing, trying to align themselves.

Just explain, don't think about how basic everything was. "For the amphibians, there's the kelpies, mermaids, nymphs and selkies, for the avians there's fairies, harpies and gryphons, humanoids are dwarves, elves, humans, orcs and trolls, and draconic races are demons, dragons, kirins, salamanders and yokai. They're all different."