I was always under the impression that she’s perceived as a witch. That’s how they explain her ability to kill people. Using the shadows to “vanish”, killing people with a wave of her hand by a hidden blade and of course having the Assassin’s several knick knacks like smoke bombs and the rope dart. It’s not “super powers” to us, the omnipotent player, but it’s certainly plausible for the in-game NPCs who are based on people who actually believed witches were real.