Through narrowed eye slits, the magic wielder felt time almost slow around her, as an arc of lightning burst out of her magical runes, thousands of individual jolts cascading together into a pure lightning bolt of seemingly limitless power, it's beauty was indescribable, each ripple slowly building together, like a thousand rivers of energy, making everything around it darken by compare. She knew the spell didn't actually affect time, but boosted her mental response time so she could keep up with it and control it, so it would not kill her allies through a foolish mishap.
Through sheer willpower, she forced all of the unbridled power to obey her, the focal point in the center of her circle, just waiting for orders, until she sent one more strand of pure white energy into it, firing off her fingertip, it shot through the center of it, and the entirety of the power became hers to command, following the single strand of power she directed, she sent it slamming straight through the armored demon that had broken free from his companions, the speed of the spell making it impossible to dodge...
Everything moved so slow around her that she almost felt as if the battle raging on was little more than a farce, she could see every blow as if frozen solid, like a picture of what was happening, moving so slowly that if not for her lightning rushing towards the scene, she might think that time was standing still. As she tried to take a breath, the very air seemed to reject her attempts to move it, remaining firm where it was, every muscle in her body denying her right to move, to blink would've seemed to have taken hours in this perversion of time, the lightning itself seeming to move at a crawl as she felt herself able to aim it.
It burst into the first black armored demon and she saw the force of it creating an explosion off of the demon's body, a shockwave erupting off of him in a slowly moving sphere as energy ran up and down the thing, all of that power, so lethal, so intense, a single narrow strand, the one Sable wielded, burst out from behind the injured thing, all of the remaining strands of energy racing back to it, converging once more as the spell continued, arcing off of the first demon, she effortlessly directed it towards the mass that was fighting Matthias.
One by one, she could first see, then feel, the shockwaves of energy as the bolt of raw power crashed into each demon, tearing through their armor, destroying their flesh beneath, ripping their very existence apart, before it swelled up and jumped off of the one it just struck, and careened into another.
"Three... Four... Five... Six..." her mind racing, perhaps even faster than Matthias could keep up as she guided every subtle motion of the raw power, in a wild dance around her ally, and destroying everything he was battling.
"Seven... Eight... Nine... Ten..." the lightning crashed into the final one, and Sable's mind rebelled against being under so much strain, snapping out of her focus as quickly as she'd entered it, the entire spell having taken less than a thousandth of a second from when it started to when it finally erupted in all directions uselessly off of the final target. She couldn't keep it going any longer, sweatdrops rolling off her face after the strain of the spell, and reality came back into focus.
She had no idea how badly hurt the demons actually would be as she staggered back from the spent runes, smoke sizzling up from the illegible scorch marks where her finely crafted figures had once been.
The only things she knew for sure was that all of the demons had been struck by it, the spell never failed to strike its target... And that she'd never used this spell before to anything short of lethal effects, yet these demons were unlike anything she'd ever fought before...
A shiver of leftover power ran down her spine as she slammed her tail to the ground, letting it discharge from her strained body, and she exhaled a soft puff of smoke, finally allowed to blink, and the world once again moving at full speed, as she turned to the fight, eager to see the results of her actions, though with a nagging fear that despite this being one of her best spells, the fight may not yet be over.