I am Sam.
I have reached the gates of Hell. I entered without fear. I met the Lord of All Evil, and we made a deal. I got back to Earth, with a task.
I have to kill 665 people before I die. If I do so, I will spend eternity as a Demon King in Hell, with my own Legion to command. Of course, I'm very delighted by that perspective...
There is one condition, though: I cannot just kill random people. There is a trigger: if they hear one simple incantation involving my name, they are eligible to be my target. I managed to make my job easier, putting this spell into a book, a famous one, so that many people will probably hear it. I am very smart, indeed.
So, after you hear the deadly sentence, I will know you. And, when you are least expecting, you'll see my shadow out the corner of your eyes. And when you turn your head to see what that was... it will be too late.
I will be waiting untill you hear my name again.
Sam I am.