Not to be confused with their more popular draconic cousins, a wyvern is LIKE a dragon, but with a number of differences that some nerd can probably educate you on. For the average adventurer, though, they're pretty much the same. At the end of the day, when you're staring down a flying lizard the size of a horse that can breathe fire (or any other element) with nothing but some steel in your hands and a prayer in your heart, does it REALLY matter if, after it kills you, it goes back to a nest or a hoard?