The Abomination below

Note: Image associated is from Ironage.media, specifically their prompt, 'The Leviathan'

Riku's day had been like many others. Woken by his parents as the late winter sun's first light struggled through the heavy, though incomplete cloud cover, he dressed as they'd taught him to before joining them for breakfast. It was a simple affair comprised of brown rice, a piece of fish each, dried seaweed, and a single egg over each rice bowl. Before beginning, Riku and his father, Haru, thanked his mother, Chiaki, for their food, eating together in almost pleasant silence.

Haru spent much of the breakfast distracted, looking like he was about to say something. However, each time Riku briefly caught his father's eyes, neither spoke, the quiet sound of chewing the only other thing audible amidst the soft sound of rainfall. As breakfast ended, husband and son thanked Chiaki once more, and she withdrew, clearing away the dishes. As Riku rose to help his mother, Haru placed a hand on his shoulder and indicated he wished his son would follow him as he left for his work, running a single forge. Just as Haru's father had done when he was a boy.

The remainder of the morning was again spent in silence, Riku learning from his father's example, copying his routine before entering the forge, until his father selected a bar of iron and hammer, striking the cold tip in a steady rhythm, turning the iron as it began to change shape. And slowly, colour. When the iron was less red than a peach but more so than a plum, Haru selected another hammer, all but identical to his, save it was half the size. This hammer, he handed to Riku, pointing at the tip, and as Riku hit it, Haru told him 'harder'. Riku struck again, the unfamiliar weight strange in his hands, and a tiny smile quirked his father's lips as he said to Riku, 'again' with a nod, turning the iron on the anvil. Each time Riku hit the bar, 'again,' his father said, and Riku soon realized he was matching the rhythm his father had shown him. Shortly after, the iron was turning not just red but orange, and soon yellow like straw, while young Riku was sweating, his arm heavier than he ever thought it could be. One last time, he heard, 'again,' from his father before Haru took the iron away and almost set the glowing tip into a bundle of straw, but the ground shook beneath them both.

Haru held the iron away from the straw, counting time quietly to himself, and the ground shook a second time, a third, and a fourth in rapid succession. Before the ground had even steadied itself under him, Haru was a flurry of movement. Dropping the hot iron into a water trough, he put the straw and his hammer back in their places and snatched his son into his arms. Riku didn't even have time to ask his father why the ground had rumbled or to let go of his little hammer, clutching it tight as his father hurried out of the forge into the suddenly busy streets.

Soldiers were already flooding the road, a motley mix of young and old, some in half their armour, others fully dressed, each armed as they rushed down the street. Riku wanted to know where they were going, at least until the answer came into view as a shudder rolled through the earth. A great beast had appeared, tall as a mountain, its every step shaking the ground. Deafening screeches emerged from its maw, drowning out the first harsh, disparate cracks of gunfire. Handfuls of arrows streaked over to the beast, each and all scoring an invisible hit or skittering off the bright plates that intermittently covered its dark hide. Upon its back stood a house for but a few seconds more. To Riku's shock, one of its many arms grabbed at the additional weight, throwing it randomly into the city, the crack of stone and heavy timbers only adding to the chaos as the beast screeched again. A stronger crackle of gunfire answered before the boom of a cannon announced itself in furious fire, buckling part of the strange plates adorning the beast.

That was the last of the fight Riku saw as Haru reached their home, entering as quickly as he could manage before finding the cellars. Chiaki was already inside, pacing between shelves and burst into tears as her husband and son joined her in the relative safety beneath their home, each praying for the monster's swift end. Without light, an unknown length of time passed as Haru held his son and wife to his chest. Every shudder of the earth, each distant peal of cannon fire, and soft crack of rifles stubbornly refused to be the last they felt or heard until one last mighty shake of the earth sent Haru sprawling, loose dirt falling on them all as the outside world fell silent. The world seemed to hold all things still until, faintly, a cheer roared from the outside world, and husband, wife, and child lent their own voices to it in jubilation.