The prompt for this was "The last Grimm on Remnant, an ancient Dragon, is tracked down by the last living descendant of the Rose clan. Just before she strikes the final blow, it speaks to her."
August Rose strode through the blasted hellscape in the mountains to the southeast of Vale.
A week ago this was a peaceful, if still somewhat rugged, shire where miners were extracting Dust that the presence of Grimm had long rendered inaccessible. But with the monsters gone, the time was finally right to move in and claim this land for humanity. Within ten years of the first mine being set up, hundreds of homes clung to the mountainside, and people began building their lives here.
Until they received a terrible reminder that the creatures of Grimm were not extinct yet.
The blight that August now walked across spread over two mountains and covered everything for ten miles around them. Not a single thing, plant or animal, was left alive. The houses and the mines and all other things that were made by human hands were destroyed so that nothing stood higher than a person's knees. Ash covered the ground as far as the eye could see, ankle-deep in some places. Smoke hung heavy in the air, defying all winds that should have blown it away and turning the afternoon as dark as midnight. Sometimes they seemed to form shapes, and it was easy to imagine oneself surrounded by the ghosts of the three thousand people that had died here.
But August did not falter, for she was the last of the Roses. Her family had saved Remnant a century prior, and their legacy gave her courage.
At her left hip was Crocea Lux, the blade that was broken forged anew, along with the shield that had never failed. They belonged to her great-great-grandfather, the knight-errant who defeated a Maiden to avenge his lost love but spared her life so as not to let revenge consume him.
At her right hip was the cane that had belonged to another great-great-grandfather, the last ever Man with Two Souls, who broke a millennia-spanning curse to reclaim his identity.
As for her honored great-great-grandmother, who slew the Queen of the Grimm and brought the promise of peace to Remnant, scythe and cloak were both lost to time. Of her, August had only her silver eyes, which she had used many times to smite the creatures of Grimm.
These heirlooms gave her the strength to face even the darkest of terrors without fear.
As August looked ahead to the space between the two mountains, she spoke aloud to herself.
"You hid for a hundred years, why do this now? And then why stop? If you meant to war against humanity, you'd keep killing for as long as you could. No, this destruction was your only goal…"
That was when August realized it. The Grimm knew it was the last of its kind, and that soon it would join its kin in death. This devastation was its swansong; these deaths were its last effort to remind humanity of the terror they once lived in.
August stopped walking. If this was the Grimm's attempt to go out in a blaze of glory, then it would come to her. She closed her eyes and took a deep breath. When she opened them again, they pulsed with silver light, cutting through the smoky haze that surrounded the Huntress. The wave of light expanded ever outwards until it was too far to be seen.
The response came moments later.
A roar carried across the land, deafening in its volume and undeniable in its purpose. This was the roar of a creature that scorned the very idea of stealth.
A moment later the monster spread its wings to the sky, wings that looked gargantuan even when framed by two mountains. These two mighty wings beat with the force of a hurricane, and the monster rose impossibly into the air. Its serpentine body coiled through the sky as it flew forward with speed that matched even the most advanced of aircraft.
In seconds it was upon August, and she saw the full horror of its form. Knotted muscle thick as cables flexed under scales that were each the size of a dinner plate. Claws great enough to pluck a Bullhead from the sky tensed as it approached the Huntress, and jaws wide enough to end a dozen lives hung open in anticipation. Its mask of bone was bigger than a house. The patterns of red that wove over that pure white mask formed inimical shapes that meant nothing in any language known to mortals and yet somehow spoke of the end of all things. Yellow eyes glowed in the center of that mask, windows to the soullessness of the last of the Grimm.
The people of Vale had named the monster Typhon, and it was greater than the Dragon that had attacked Beacon Academy in every way save one. This monster could not spawn more of its wretched kind. Not a single new Grimm had spawned anywhere in the century since the death of Salem.
This creature truly was destined to be the last of its kind.
Typhon spread its jaws, and azure flames erupted from its maw, hot enough to melt stone. In an instant, August donned her shield and raised it in front of her. She ran her Aura through the metal of her family's eternal bulwark, and as the fire engulfed her she felt nothing more than a desert breeze.
When the flames died down, August drew forth her cane and extended it to its full length. She pointed the weapon at her foe, and the tip flashed with the light of a star. An instant later a perfect circle wide enough to drive a train through was carved into Typhon's wing. The dragon roared its outrage even as its body fell from the sky. It crashed into the ground a hundred yards away from August, and she was nearly thrown from her feet by the force of the impact.
Even as Typhon rose onto its legs, August charged forward, returning her cane to her belt to draw out Crocea Lux. The Grimm turned its gaze on her, but then flinched back as silver light began to pour from her eyes. The light cut through the miasma that covered the land, banishing the smoke that had refused to subside.
Still, like a man charging headfirst into a hailstorm, Typhon advanced through the silver light to meet its foe.
The fight was a blur for August. She remembered hacking and cutting with her ancestral blade for what could have been hours. She remembered batting aside teeth like swords and talons like spears, always inches from death. She remembered bringing her weapon down over and over to strike scales like tenfold shields. But finally, when her Aura and her strength had all but given out, Typhon broke, unable to fight any longer.
August advanced on her fallen foe, sword and shield still at the ready. She found a spot on its neck where the scales had broken, where she could land a killing blow.
"Typhon, last of the Grimm," she called, raising Crocea Lux. "With this I end the blight your wretched ilk have brought to the Rose family and to Remnant."
Typhon's body shook, and a rumbling echoed around August. She whipped her head around, confused. It sounded as if the Grimm was… laughing at her?
"Is it truly I that am the blight upon your family?" asked a voice that rumbled like thunder.
"W-what?" whispered August, as perplexed by the Grimm's words as by the fact that it could speak at all. She lowered her sword as the light in her eyes died down, and for the first time since encountering Typhon, she felt very small.
"Was it the Grimm who made you the last of your name?" demanded the monster. "Was it we who sought to control the power of the silver eyes or see it extinguished? Was it we who hunted you all your life? No… that was humanity."
"You… you're a Grimm!" August stated fiercely. "If you can speak, you do so only to cause pain!"
"Yeeesssss," agreed Typhon. "And what words could be more painful than the truth? It was humanity that forced you to live in hiding. It was humanity that made you an orphan. And it was humanity that plunged Remnant into war mere decades after your ancestors brought peace. The darkness in their hearts far eclipses that of the Grimm!"
"Is this supposed to convince me to spare you?" demanded August.
"No," hissed Typhon. "Only to show you who your next target should be."
"You want me to become like you? That will never happen."
"You protect a world that hates and fears you, little warrior. You risk your life for them. Why are they worthy of your sacrifice?"
For a moment, August said nothing. She stood there motionless, eyes cast towards the ground. Finally, she spoke.
"After my parents were killed, I was alone and had nothing. I wandered the streets of Vale, sick with grief and dizzy with hunger. Most people ignored me. But then, a little girl came up to me and gave me a piece of cake. She said I looked like I needed it more than her. It wasn't much, but it kept me alive long enough to find help."
"And that redeems them all?" demanded Typhon, scorn in its voice.
August looked up at the ancient Grimm.
"Yes."
The Huntress raised her sword and plunged it into the gap in Typhon's scales. Her eyes glowed with silver fire that spread and engulfed the dragon's entire massive form. This argent beacon grew until it could be seen for miles, casting back the miasma that had fallen over the land and dispelling it forever.
"That and the boy that gave me his coat when I was cold. And the woman that helped me escape the kingdom's agents in the city. And the couple that raised me when my own parents were gone. And the man who kept my family's relics safe until I was old enough to claim them. And all of the people who helped me get justice for my parents' deaths. There may be darkness in the hearts of humanity, but there is light too! And I will never stop protecting that light!"
When the silver light subsided, nothing was left of the ancient Grimm. After thousands of years, her family's mission was finally complete, and August Rose stood alone in the afternoon sun with no one to see the tears in her eyes.