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 Cats anime adaptation features some characters not created by Yabuki, as well as many plot differences. Main characters Train Heartnet , also known as , is the protagonist and a Sweeper partnered with Sven. Train is a light-hearted, courageous man who is highly skilled with a gun. The 23-year-old's distinguishing features are a choker with a tiny bell attached to it and the XIII tattoo he has on the left side of his chest. Two years earlier Train was a Chronos Number, a ruthless assassin and Number XIII of the group. He has a large amount of killing intent that he honed from his days as a Chronos member, and as a result he often has sudden mood swings, going from carefree to serious in an instant, especially when Creed is mentioned. This personality stems from being orphaned at 10 years old after the assassin Zagine Axeloake kills his parents, takes Train in and teaches him how to kill with efficiency. Zagine eventually dies and tells Train that he needs to be the strongest in order to survive. After that, Karl took Train in and he became an assassin for Chronos. Having been killing and exposed to death since early childhood, Train becomes very bleak and unsmiling until he leaves Chronos. He eventually meets Saya, a carefree sweeper, who slowly changes Train into a "stray cat" that does not blindly follow orders. He decides not to kill anymore, and after Creed kills Saya, he leaves to become a Sweeper and searches after him. He wields , a black and gold revolver made out of Orichalcum weighing 2.5 kg, with the numeral XIII engraved into its side and a red tassel attached to its hand grip that stretches out like a leash. He possesses 20/20 vision and is an extremely skilled marksman, able to accurately shoot down bullets from other guns, and hit the same place with a number of bullets at exactly the same time. He is ambidextrous, but naturally left-handed; using his left hand increases his speed and accuracy. He can also