Jingliu

She was sitting on a bench waiting for her arrest.

The mirror-like blade showed her reflection. Then, a swarm of razor shards swirled up in a tempest, dragging the girl into her past —
In the dimly lit sky, the demonic planet named Rahu was wailing and singing, hurling towards everyone with lands and mountains ablaze.
On the streets, people were screaming, writhing and rolling in apocalyptic despair, as the golden tendrils sprouted and grew feverishly in every orifice of theirs.
She watched everything unfold, paralyzed. Her organs felt like they were boiling. Something suddenly surged and churned in her Core Esse, like a ripe wheat grain about to burst out of its husk and swell to infinity.
The mountains hurling towards her face made her realize, she was but a mayfly, about to perish at the mere flick of an Emanator's fingertip.
In that split moment before death claimed her, she grabbed the only thread she could hang by.
A sword, 3 feet and 7 inches in length, weighing about 7 catties.
A sword, 6 feet and 5 inches in length, weighing 14 catties.
This is a Cloud Knight greatsword that must be wielded with both hands. Its edge contains enchanted fire that can split open the mechabeast's inert armor at the moment of contact.
There are 12 Flying Swords providing support, connected into her spinal meridian from the acupuncture points of Dazhui to Yaoyangguan. She needed only to think for these swords to instantly span out like a blistering storm.
She was still unfamiliar with the way of the sword. She still had lots to learn.
The woman in armor had no time to teach her more before the woman was tasked with leading the army on the field. Therefore, the girl's second lesson is to be learned on the battlefield, taught by the enemies she would fall.
"Stab" is easy, but swift monsters won't run into the sword's tip on their own or let the girl execute them. That is how she learned "slash."
"Entangle" is next.