the technical term for the blade's mechanism of effect is "pseudosingular non-Riemannian manifold collapse". the only things that can stop it are metric shielding or another PNMC weapon, both of which will cause emergency shutdown in the blade to avoid catastrophic failure.
it is also incredibly energy-intensive. cutting through six meters of typical combat armor would use up the doll's entire energy reserves. it is a weapon of last resort for small targets that must be dealt with at all costs.
PNMC swords (pronounced "pin-mick") are sometimes called lightsabers for the obvious reason. this doll doesn't do that. she's not a fan of most pre-baozha media. treats robots terribly.
hers is named Durandal.
it shows her its weapon. or, well, the hilt of one. intricate, inlaid with the same symbol that adorns the doll's uniform. but--
"where's the, you know, sword?"
it points the hilt up. "cut, o blade of void." there's a rush of air, and three feet of what appears to be metal spring into existence. but the reflection is perfect, and light bends around the edges like a black hole.
it picks up a stone that was on the ledge. "watch." in one motion, with one hand, she passes the blade through it left to right there is a quiet hiss, a faint click. nothing happens. the stone is whole. until it gently nudges the top half of the stone with a finger, and it slides clean off the bottom half. the surface of the cut is geometrically precise. she runs her hand over it, and can't feel any roughness.
"impressive. but do you really have to say that every time you turn it on?"
the nothing-blade flickers out. "no, it's a cryptographic handshake keyed to my ID module. i just like being showy. especially to impress girls."
"well, it worked."
they grin at each other.