Because you like Princess Zelda in The Legend of Zelda
Marv is a brutish but principled thug who'd be right at home on an ancient battlefield. See them in Sin City.
Walter White's knowledge of chemistry allows him to cook astoundingly pure meth, leading to a rapid – albeit tumultuous – rise in the criminal drug world. See them in Breaking Bad.
If Lisbeth Salander can hurt a bastard who deserves it by digging up stuff about him, she feels good. See them in The Girl with the Dragon Tattoo.
Kathryn Merteuil may be a vain sociopath, but you won't be able to look away. See them in Cruel Intentions.
CIA operative Carrie Mathison is on a self-assigned mission to follow a lead, whether it be the truth or just her delusions playing tricks. See them in Homeland.
You'll never get Alaska Young. And that's the whole point. See them in Looking for Alaska.
If you died and came back to life, and then died more times and came back, you might stop battling evil mutants. Not Jean Grey. See them in X-Men Series.
Jane Smith is a stone-cold killer, but you would never know it from looking at her. See them in Mr. & Mrs. Smith.
Lady Bird's heart is in the right place, usually, but even the purest of people can fall sway to the havoc-wreaking traps of senior year. See them in Lady Bird.
If you hang out with Bender in cool dive bars in 31st century New York, make sure you're on his "Do Not Kill" list. See them in Futurama.
A conflicted small-town preacher, Jesse Custer leaves an unexpectedly bloody path in his wake. See them in Preacher.