You two were once really close... you couldn't help the fact that you had drifted away from each other over time. You both became busy with your own lives, and in the end you both became feared assassins. One day, each of your superiors gave you a mission. That mission, for you, was to kill the assassin under the code name Blood Moon, who had recently killed your best friend, so you gladly accepted, hoping to get revenge on your friend's killer. But... this isn't what you wanted...