I Was Reincarnated as the Prince in a Villainess Story, so I’ll Use My Cheat Knowledge to Create a Noble Lady Harem and Make Them All Happy - 49

Chapter 49: The Battle of Beltea Capital — The Annihilation of Biblos

ーーーーーーーーーーーーーーーーーーーー

The walls of Beltea’s royal capital were shrouded in miasma darker than the setting sun.

Broken flags, half-melted gates. From the seams between the cobblestones, a soot-like mist welled up quietly—unceasingly.

At the head of the army stood King Ars, his dark blue cloak snapping in the wind. Beside him was the captain of the royal guard; behind him stretched a line of silver-armored soldiers. The supply units had already been entrusted to Marquis Agreia’s reserve force, and with spears and shields in formation, the army advanced.

“Let’s go.”

His voice was low, yet it carried far. The signal bell rang three short times. At the sound, the royal guard surged forward. Breath leaking from gaps in their armor turned white all at once, and the chill air heralded the beginning of battle.

From the shadow of the castle gate, it emerged—slowly, heavily. It held twin blades, and the seams of its shell ran diagonally from shoulder to hip. Its rock-like skin pulsed with red veins, and its massive limbs crushed the cobblestones beneath them.

The demon god—Biblos. According to the messengers’ reports and field confirmation, this was the very creature the Beltean populist faction had summoned using the heretical magic Valcode. Old war chronicles described the Biblos species thus: 『They exhale miasma, summon Imps, and possess the power to hold an army at bay alone. However, they have no will—only the instinct to reap life. A magical lifeform. Even their summoners cannot control them; eventually, they devour their own masters.』 That was the conclusion the records had reached.

At their feet, miasma frothed like a pool of black water. From it, small beast-like silhouettes began to crawl out one after another—Imps. One arm was a spiked spear, the other stretched long like a tongue. Their eyes were white and cloudy. Their breath reeked of rot.

“Maintain the purification line!”

The clerics in the rear all swept their robes outward at once. Centered on Milia, the radiance of Divine Arts spread, and the miasma thinned slightly. Yet, like skin peeled away, it was immediately replenished. Its density was growing once again.

The miasma revealed three faces as it deepened. Pale violet—Mist. Ash-black—Mud. Jet black—Flame. At the Mist stage, knights could still fight, though with difficulty. At the Mud stage, a heavy pressure clung to the gaps in their armor, dulling movement by half a step. At the Flame stage, any exposed skin went numb, and each breath seared their lungs. Each time the light of purification reached them, Flame receded to Mud, Mud to Mist, and Mist eventually dispersed.

“Frontline—advance! Cut and withdraw!”

Ars hefted his greatsword upon his shoulder and charged head-on. The twin blades crossed like lightning, scattering sparks. At the instant the blades locked, a red sigil ran from Biblos’s right shoulder to its left hip, amplifying the power of its strike. It was a twin-blade technique—Monzura. Power coursed along the glowing lines, increasing both weight and speed—a signal of rising momentum.

“Fall back!”

Ars twisted his blade aside, creating distance with a shove of his shoulder. The royal guard split left and right, cutting and retreating, retreating and returning to the healing line. Time was governed by bells and banners—thirty breaths per rotation, banners shifting from blue to white, white to black. In the fleeting moment of transition, the miasma flared to Flame again, but Milia’s prayer forced it back down.

“For now, we destroy through defense.”

Duke Balmuth’s voice spread through the ranks, carried by the runners beneath his command. The northern army knew well the nuisance of demon attacks—small groups and their swarming nature alike. Courage never lasted forever. Discipline held only when it outweighed fear. That was why rotations were needed. Why purification was needed. Why there had to be a reason to breathe in unison.

In the rear encampment, Duke Balmuth sat before a map table, resting his hand upon a special command board. Upon it were drawn the lines of the keystone network, the streets, and the overlaying colors of miasma density.

“Activate variable formation. Set the banner mark to ‘Moat.’”

An aide placed a small red flag upon the outer ring. The command board’s runes clicked sharply, and several breaths later, earthen walls rose in the alleyways of the battlefield. The delay was seven breaths—this was the time lag between banner signal and terrain generation. Brief, but fatal if misjudged.

This terrain-generation tactic was no improvisation. The concept had come from Duke Balmuth; the design, from Valis. The working force was Spirit Arts, and the reins that controlled it were Archive Arts. A true hybrid weapon system. It had begun at the War Office’s strategy table.

『Even in annihilation battles, inexperienced young knights will break unless they fight within a defensive formation. Urban terrain is full of corners—our lines collapse easily.』 

Duke Balmuth once said.

『Then we’ll make it possible to create the lines themselves.』

Came a reply from Valis.

The method was simple in form. Using the keystone network as a base, they built walls,  ramparts, and moats using Compression of Earth Spirits. Air Spirits were used to clear dust to preserve visibility. Long-range control was achieved through an Ancient Magic Array, converting banner → coordinates → terrain through encoded runes. Failsafes, rollback protocols and safety arrays were implemented to prevent misplacement or loss of control. Field operation was straightforward: Place a banner, wait seven breaths, a wall rises. It was simple, but built upon dozens of failed tests and countless clauses written to ensure no soldier would ever be trapped inside.

In simpler terms, it was “the art of bringing trench warfare’s advantages into urban combat.” In cramped alleys, soldiers tended to scatter and get shot in the back. But when aligned along a line (a trench or rampart), they faced forward together, and the paths for rotation / rescue / retreat remained alive. If magic could generate those lines in real time, then one could annihilate while defending. That was the idea.

“Ramparts, Alley Two. Moats, Three in front of the gate.”

The dust cleared with the Air Spirits’ breath. Walls condensed by the Earth Spirits grew dense cores, trench edges stood firm. That meant no soldier would lose their footing. The trench to retreat through, the step for the next line to advance from, the cover to seal off the Imp-spawning pits. Duke Balmuth laid and lifted his flags one after another. The terrain changed on the board and the city was gradually rewritten into their own fortress.

“Press by front, defend by line, and split by wedge.”

True to those words, the map changed color with each passing hour. Supply routes ran through the bellies of the variable formations, and safe zones stretched like bands. Marquis Agreia’s units moved along that band, carrying water, gruel, bandages—and the road home.

Meanwhile, the outer ring waged its own battle. Goblin swarms fell to arrows and spears, but orc warbands were heavier. Wall-pushing tactics were required to drive them back. By “pushing” an earthen wall forward, the orcs instinctively fled the opposite way. Where they fled, ramparts awaited; beyond the ramparts, spears. Encircle by area, strike by point.

Fortunately—or perhaps unfortunately—hardly any civilians were found alive. There was no reason to hold back. No reason to hesitate in full-scale area suppression.

And then—the core.

Biblos leveled its twin blades horizontally, sliding forward half a step at a time. The left blade low, the right blade high. The red sigils in its shell lit once more, shifting into Chasing Sigil, the follow-up of the twin-blade form. The crossing angle changed from sixty degrees to forty-five— an angle meant to carve flesh. Deflecting was the only right answer and only Ars could read it in time.

“Stand down. I’ll take this one.”

At the king’s command, the second line of the royal guard stepped back. The greatsword fell vertically, “entangling” the twin blades and forcing them outward. The back of the blade struck stone, scattering sparks. Biblos roared. The miasma flame wavered back into Mud stage, and in that fleeting lightness, the guards found their breath again.

But it would not last. The miasma thickened, their arms grew heavy, their vision narrowed. Only a few dozen held the line—rotating forward, but in truth, only one could face it directly. The king’s armor and greatsword bore wards against magic—spoils from his adventures in youth. That was why he endured longer than anyone. Yet even that endurance had its limits.

By the fifth day, red markers had moved outward on the map, blue ones inward and the surface reclamation of the royal capital was finally nearing completion. Only one shadow remained before the gate. And now, the gathered forces were enough to unleash an assault stronger than Biblos’s regeneration.

“—Your Majesty, allow me this time.”

The voice belonged to Reina, clad in blue armor. Having led the spearhead of the suppression lines, she now joined this final front.

One step forward.

Her blue plate gleamed white in the light, and her drawn blade sang softly. Miasma flames burst at her armor’s edge, black soot falling upon her shoulders. Yet her breathing remained steady.

Without a word, she stepped into the range of the twin blades—not to block, but to deflect, to entangle, and to sever the light of the sigils with the flat of her blade. She cut through layers of miasma, advancing lightly, eyes fixed only forward, as though she had forgotten how to retreat. Faster than the dual-blade technique “Monzura,” Reina’s sword shifted its angle and stole the direction of the creature’s weight. The giant body wavered slightly.

Even the miasma released by Biblos, which had tormented even Ars, did not faze her—instead, with a force that seemed to push the miasma back, she continued her relentless chain of sword strikes.

The ranks of the royal guards, ordered by Reina to time their movement with the king’s recovery, all drew in a breath at once.

“Milia-sama, over here!”

It was Marquis Agraia’s command. Waiting at the flank of the front line, Milia swept her robe’s sleeve aside and began to weave a prayer of Divine Arts, the holy magic. Threads of light streamed into the king’s armor, untying the fatigue deep within him. His once-heavy breathing grew lighter.

“I shall return.”

Ars readied his greatsword again and stamped the ground. Reina took a half-step back, her twin blades intertwining once more before flowing outward. In that opening, the king’s blade fell. The blade sang. It pierced the center of the giant’s body—the crossing point of the red sigils. The swirling miasma drew in a single, deep breath before scattering into mist. Seeing that, the royal guards and gathered knights launched their assault all at once.

The imp collapsed into Mud, leaving behind only black ash on the stone pavement.

“—It’s over.”

With Ars’s voice, the demon god crumbled.

The report reached the southern supply base in the shortest possible time. Valis unrolled the parchment and let out a long breath.

『Capital secured. Biblos annihilated. Losses, minimal.』

His chest went cold at the line: “Reina once engaged the demon god alone to hold it back.”

Yet the words that followed burned with heat. “She seemed stronger than the king.” “A battle maiden possessed her.” —a report written by the royal guards, still in the throes of excitement.

Cold and heat—both lingered within him at once. Even so…

Never again will I let her stand on that field. For that, I must…

Valis placed his finger on the map and began to draw recovery lines around the royal capital, one by one. Water first, then sanitation, food and order. The war was over, but what came after was his duty to carry on.

“From here on, it’s my turn.”

He murmured quietly, extending the first line with a smooth stroke.

ーーーーーーーーーーーーーーーーーーーー