Darker Than Black is an anime from 2007 with a second season and an OAV that I haven't seen but very much want to. It takes place ten years after two reality twisting anomalies appeared on earth, one in Brasil and the other in Tokyo. They are known as "Heavan's Gate" and "Hell's Gate," respectively. When this happened the sky was changed so that the moon was no longer visible and the stars were replaced with new ones. What the general public doesn't know is that these new stars correspond to people now known as "contractors" who have lost all of their emotions but gained supernatural powers, turning them into the perfect killers. Whenever one of these contractors dies, their corresponding star falls. Every major government (and some other non-political entities) use these contractors as assassins and agents to collect information. This in and of itself isn't very new, all sorts of shows (such as S-Cry-Ed, Heroes, X-Men) have similar ideas with people gaining unique powers, but Darker Than Black does add a new dimension, though. While contractors each have unique abilities, (ranging from teleportation, to pyrokenesis, to freezing stuff, to blowing stuff up) they also have to pay a price (called a "remuneration" in the sub) these can range from obsessive/compulsive actions (setting stones into a grid, putting people's shoes upside-down, kissing people) to the uncontrollable (falling asleep, aging more quickly, aging backwards).
