Who Started As A Love Interest, But Then Became A Fully Fledged Hero?

Heroes need sidekicks, enemies and mentors — but most of all, every hero needs a love interest. And sometimes, the love interest helps out here and there. But which love interest shook off that role and managed to become a completely formidable hero in her or his own right?

Please include a picture, book cover, comics panel or clip for your chosen love interest. And please mention his/her name, where he/she appears, and the nature of the transformation from "love interest" to "ass-kicking hero who is defined by nobody else." Thanks!

Top image: Pepper Potts. By the end of the third Iron Man movie, she's got her own superpowers and is ready to smack some Extremis goons around.