[Evil is far too simplistic.]

Ravenna sought power. She lost everything when she was a young girl and was essentially powerless, subject to whatever the men who destroyed her village were wont to do. All she had was her beauty where her power was tied. But as she grew old and her looks began to fade, her power began to fade as well.

If she consumed my heart, she would have lived forever and remained youthful and beautiful. Beyond that, I cannot say for sure.