After Stabbing My Old Club in the Back, I Lost My Memory.

My name is Cao Ren, a shop waiter who has lost his memory. This mission is for a dandy. The client is the most terrifying organization in the world, and I have their mark tattooed on my back. They said that I was once the most powerful killer in the world, but now, I just want to be a good person. (This is a story about memory and choice.)