9. Black Widow
Since her introduction to the world of Marvel comics way back in 1964, it's possible that Natasha Romanoff has never been more popular than right now. With her solo movie set to be Marvel Studios' very next release, excitement and intrigue surrounding the character is greater than ever before, which is truly saying something.
Initially introduced as a Russian spy for the KGB, before soon defecting to the US and the Avengers, readers couldn't be certain about her loyalties or her true intentions. Naturally, this wasn't helped by her moniker and the details of her past.
After all, how likeable can a trained assassin be? She has a very chequered past, and Loki's sentiment from Avengers Assemble is as relevant for the comics as it was for the movies: can you wipe out that much red from your ledger?
Once Natasha solidified her role as an Avenger, surviving short lived collaborations with Spider-Man, Daredevil, and her own solo series that lasted just eight issues, she began to grow in popularity. Even with her less than virtuous past, and history of squaring up to some of Earth's Mightiest Heroes.