I had a question about Coup de Grace.
It says you can use it against a helpless opponent. Helpless opponent is defined as "Paralyzed, held, bound, sleeping, unconscious, or otherwise completely at an opponent's mercy."
Now, if I was invisible and behind an unwary opponent, could I use a Coup de Grace because he'd be 'completely at my mercy'?
I've read things in places that this might indicate a yes, but I wanted a definitive answer.
EDIT: I was just using invisibility to set the stage. The point was that the victim has no idea I'm there. Invisible, or not, I just wanted to know if this situation counted as a coup de grace.