Because you like O-Ren Ishii in Kill Bill vol. 1
Marv is a brutish but principled thug who'd be right at home on an ancient battlefield. See them in Sin City.
Jean-Baptiste Grenouille may have a phenomenal sense of smell, but he has a weak sense of morality. See them in Perfume: The Story of a Murderer.
Emma Woodhouse knows what's best for everyone else. Just don't try to tell her what to do. See them in Emma.
A fight every now and then makes Dante's life a little more interesting. See them in Devil May Cry.
Although Morrigan knows every kind of magic there is, friendship is an untested area for her. See them in Dragon Age Series.
Handsome Jack is wearing a mask of his own face to hide his scarred real one. See them in Borderlands Series.
A soulful bass player, Nick O'Leary can't stop sending breakup CDs to his ex. See them in Nick and Norah's Infinite Playlist.
Driven, resentful, and ruthless, Mello is an emotional powder keg. It's only a matter of time before he explodes. See them in Death Note.
Waylon Smithers would do anything for his boss, and would love to do a few things *to* him. See them in The Simpsons.
A self-professed psychopath, James kills small animals for fun. After getting bored of that, he is ready for an ambitious murder. See them in The End of the F World.