Brass Dragon.
In fact, it was really hard for Soran to think that this cute Lolita had anything to do with an adult Brass Dragon. However, most of the dragons were magical, so it was not so difficult for them to have human forms. It was just that many dragons didn't like to change. In the case of changing into other creatures, their combat power would also be weakened.
Polymorph.
Greater Polymorph.
There were many spells that could change a person's appearance, but retaining power was the difficult part.
