The Assassin(Black Butler x reader x Diabolik Lovers)

She had cold eyes, a dark mind, and a heart blazing with the fires of hatred for those who look down upon her. She is the world renowned assassin, known as The Reaper, or The Fallen Angel. She always wore a mask, not matter what the task was. Her identity itself is not known by anyone, much less so the Queen's Guard Dog and Spider. They were tasked with tracking down the elusive killer, as well as identifying her when it was rumored that she had come to London for a job. But, she is not the only thing they were to track. They are also tracking the group she is allegedly the leader of that was notorious for killing of rival gangs across the world. Nobody has ever known the real name of the group. But, their assassins are known to say, "Mín gar- arrived, cin tur-'t nor-, cin tur-'t deli-. Whui ú- just on- or- hi? " before killing the victim. Nobody could decipher it, but nor did they care...