I am toying with the idea of having dragons take human form in my fantasy book. There have been cases in which dragons do this such as World of Warcraft and Dragonlance. When I think of a dragon in human form, I envision them being similar to high elves in that they are tall and inhumanly beautiful. However, they would be covered in soot and smell like ash. I will tinker with this further as I continue writing.