Any fan of more serious anime, and less kawaii... I can't recommend Darker Than Black enough.... Provided you can find it. It's wonderful.
@Darnell And there's one in particular, the Black Reaper, who has no cost to pay for using his powers... He's the hero of the show, and is trying to uncover a nefarious plot as to why the stars fell and what's going on with the "contractors" (people with powers) and "dolls" (people seemingly taken over by spirits of sorts)
It's by the same people who did Cowboy Bebop... Also, incredible soundtrack.
@Darnell The guy in charge of the English dub (best English dub I've ever seen btw, they didn't just translate, they adapted culturally) said "If you like Fringe, The X Men, and Batman the Animated Series, you'll like Darker Than Black" and he isn't wrong there.
That's the best description I can give. Stars fell from the sky, Tokyo is walled off, and there's people with odd powers lurking in the shadows, but if they use the powers, there's a price they pay each time. Detective discovers them...