Black Cat, Vol. 1
Title: Black Cat, Vol. 1
Author: Kentaro Yabuki
When Train Heartnet, also known as “Black Cat,” decides to quit being an assassin for a secret organization to live life on his own terms as a bounty hunter, he soon discovers that his past is not easily left behind.
Two years ago, Train, a high-level assassin known as Number XIII in Chronos, left the secret society to live by his own rules. Since then, Train has been a sweeper, a bounty hunter, catching criminals and bringing them in alive. But his main mission is to find a former Chronos member who killed his best friend.