Black Cat

i'm reading a good manga called Black Cat. i just started it, so i dont know too much about it, but apparently the main character who is the Black Cat is a famous gunman, who had quit a large organization to become a sweeper. (a bounty hunter) i believe his name was Train... not too sure though. so far that's all i know. but i'm going to continue reading it to find out more. it's quite interesting.