These sorts of things are fun! Haha, through additional details, you should answer your own! Here are mine:
1. Batman (by the technical definition of superhero, he is one, despite no superpowers!)
2. The Joker (Heath Ledger's especially, though the character himself is amazing)
3. Cujo (from Stephen King's "Cujo")
4. Randall Flagg (from Stephen King's "The Stand," and "The Dark Tower series." A sort of apostate of death, otherwise known as the Ageless Stranger, among so many other names and reincarnations, he is the embodiment of evil and darkness and all things wrong. Haha, or as he was also called, the devil's imp)
5. Abby (from the movie "Let Me In." I never thought a vampire would resonate or affect me so deeply)
6. Clarice Starling (from "The Silence of the Lambs," by Thomas Harris)
7. Barton Fink (from the movie "Barton Fink")
8. I don't know any ninjas really, except for the original Teenage Mutant Ninja turtles from my childhood! Don't make me choose just one...haha!
9. Probably a bit predictable, but Captain Jack Sparrow of course!
10. Dale Barbara (from Stephen King's "Under the Dome")
11. The main character (sort of Tyler) from "Fight Club"
12. I'm not entirely sure what you mean by mutant, but I know that term is used in X-Men, and Doctor X is amazing! Haha
13. Connor, from Assassin's Creed 3
14. Aragorn, of Lord of the Rings
15. Roland Deschain of Gilead, from The Dark Tower series, by Stephen King
Cheers!