It may seem a little contrived at first that there are already rumors circulating about an "Emperor's Hand" that carries a lightsaber, given both how secretive Mara's position is and the fact that she hasn't been active all that long. However, as Mara later discovers, there are actually over a dozen Emperor's Hands running around, most of whom carry lightsabers! Most likely, the rumors weren't caused by the actions of any one Hand, but rather all of them being active at one time throughout the Empire.
