Black Cat

Chronos, an organization bent on world peace, rules one third of the world's economy. To maintain the balance of the world, Chronos is therefore essential, and there is a need for people to protect Chronos. Thirteen special elite assassins each possess unique orichalcum-forged weapons and are called the Chrono Numbers, assassins who work for Chronos. When the thirteenth Chronos Number (Train Heartnet), also known as the infamous Black Cat, meets a Sweeper (licensed bounty hunter) named Saya Minatsuki, Train's morals and values are changed from those of Chronos's to those of his own.