Board Thread:General Discussion/@comment-5583089-20140617224509/@comment-5834856-20140619121158

Utter solitude wrote: It seems the more cold and ruthless you are, the more powerful you are.

I agree with you. They always say Magic is about emotion. The more you hate, the more dark magic you can use.

I noticed something watching ABC's Once Upon a Time. Taking all the "bad" wizards and witches into account everyone of them was established to be more powerful than The Evil Queen. Her mother Cora is stronger than her. Rumplestiltskin has more experience and is stronger than Regina. Zelena defeated her sister. Yet,so far, Regina Mills is  the only sorceress, who has been able to change her source of power from dark to light magic. (Episode 320 Kansas).

The more you use strong hatred or love to wield magic, the less you're able to change. I'd doubt Zelena or Cora would have ever been able to  use light magic. Same with Emma, I think she's a too powerful sorceress of light magic to ever be able to use dark magic.

They're powerful if they have access to their favorite source but they aren't flexible.