Darker than black is a bit complex but it has a really cool concept.
Pretty much there are these types of humans born called "contractors". They are born with super powers but unique things like being able to stop time for a few seconds or negate gravity. One can even cause peoples internal organs to fail.
However they all have to pay a price for using their powers. After they use their power they have 24 hours to pay their price. One guy can use telekinesis but after he uses his power he has to break two of his fingers as his price every time. They heal instantly after the break but he feels the pain etc. Another girl can stop time for a few seconds but she ages every time she does it, that's her price.
It's really interesting. Oh and the "dolls" are another type of human in the anime. Just different powers.
I suggest you check it out.
P.S/EDIT: One of the characters can sing and cause vibrations that can do serious damage to wherever she directs it but her price is to throw up naturally. So she can't force herself to do it. So she has to pick up bugs and chew them or disgust herself with something. Some of the prices are very odd. (Which keeps things interesting).
Last edited by Rainbowz; Feb 24, 2014 at 04:47 AM.