what's an interesting supernatural being?

Well other than being tall - a leprechaun could be cool. Maybe a modern one which isn't restricted to a small size? She can lure people in with tricks and tales and grant them 3 wishes which always backfire and put people in the most dire situations. They're very fast, cunning, smart and strong willed/witted!

Also, look up the faceless ghost of Japanese folkore - real creepy and eerie!

I think wendigos are very intriguing...

There are many variations off of the legend, but my personal favorite is people who commit sinful deeds (the most common being cannibalism) transform into a shapeshifting beast.

The beast can take any form it wishes for, as long as it constantly feeds on human flesh. When the source runs out, it becomes the true monster, large, gruesome, and wretched.

They're basically like the native american zombie.

That is from a book i have already finished, and soon to be published.

Make her the spawn of Satan.