What would I call this character?

She's rich and powerful and owns many things.
What would she be called? A aristocrat? Countess? A noble woman? Like what?
She's not royalty. Just is stupid rich and powerful.

(BTW she's also dark,sadistic, and hedonistic)

Like I'm trying to write something
"Madam Crow. She is a dark [aristocrat?] Who -" you get me.

So what is she called?