The Black Cat manga series features characters created by Kentaro Yabuki. The story follows a young man named Train Heartnet who withdrew from an elite group of assassins called the Chronos Numbers two years earlier and is now a Sweeper, or bounty hunter. Many of the characters are humans with superhuman strength, speed and/or supernatural abilities. Black Cat's anime adaptation features some characters not created by Yabuki, as well as many plot differences.