We can surmise from Gracebearer's rejection of her ancestor's memories and lack of wind magic that she doesn't practice or employ arts, or at least not consciously.
Talk after Trust Increase 2 Let the ancestors' legacies lie forgotten in my mind. It's enough to pick up a few tidbits from time to time as tales to tell the children. What I really want to remember, well, is the excited looks on the children's faces when I talk with them... and the smile on your face right now.
So that being said, unlike Mantra who can actively use telepathy and other psionic attacks, or Phantom who employs psychologically melting mind control magic courtesy of the troupe, that Gracebearer employs other means to apply nervous impairment.
I choose to believe that the way she fights is so intimidating and scary and gory that not only being subjected to it, but watching it is enough to apply nervous impairment, which is why she urges the Doctor to not observe her combat.
Added to Squad I would be delighted to join your team, Doctor, but... I'm hoping you will stay away when I'm fighting. Maybe you wouldn't mind it, but to me, you're too good of a person to have to face that.
In Battle 1 Close your eyes. I don't want to scare you.
In Battle 2 Cover your ears. This might get loud.
Fucked up and scary snake woman that kills and disembowels people so good that it will deal psychic damage on par with the horrors.
These lines suggest the implication that other people; not just children, have observed the effects of her fighting and it's been a disastrous enough outcome to warrant her issuing warnings beforehand to try and avoid the same outcome. So overwhelmingly negative that she chooses to try and hide her capability of inflicting such harm.
What allows her to rip people apart so effectively that, unlike other operators- surely Lappland or Surtr do awful things to the human form- either the sound of meat tearing or the screaming of people as they get mauled resounds through the air?
