"Witch? Hate to disappoint, but magic isn't something I can do... That's called a Semblance, and it's just a tiny bit of my soul is all."
He looks wide open, but Blake doesn't win fights by charging in as if she's Yang. Instead, the girl would quickly back away, moving far faster than any human has a right to as she aims to take cover up in a tree. From there, she'd pull a red vial out and toss it into Gambol Shroud, she smirks as the fire dust runs through her weapon and into a set of 6 clones. This set rushes straight for him at various angles, 2 at the front and back, plus one for each side. They're aiming to close in and flail their fiery bodies at the demon.
Of course, if he countered them at close range, he might not like the resulting blast of flames that pop up where they "die". Finally, Blake herself would begin darting between trees, flicking her weapon into a pistol and firing off a blast of flames every few braches, 3 shots to be exact, one above him aimed at the skull, another to his back, and finally one aiming for the singed arm to burn it some more.
"As for what Grimm are, honestly even I'm not too sure since nobody seems to know. But, I can tell you they slaughter people without even thinking, though such things don't speak much unlike yourself."
Even as she delivers exposition, Blake's still moving about the trees and never staying in one place, almost giving the effect of her voice echoing through the area.