The great thing about fairy tales and myths is that they go beyond character. They're not about character. They're about more basic things. They're about basic fears or longings or desires or fantasies, and stuff like that.
It's hard to know whether certain characters come to life or not, they either come to have their own life or they don't. I've written many things in which the characters just remain inert.
For example, the character of Claire in In Dreams wasn't imagined enough by me. Annette Bening is a great actress, and she gave a great performance, but because I hadn't fully written it essentially the character wasn't finished.