Li Zi-song immediately fulfilled everything Dong Bong-su had requested.
He transferred all hundred or so Whirlwind Artillery pieces to Dong Bong-su, withdrew the position to where the southern Yellow River's shore was located, and had all the corpses who died from the epidemic moved to the vicinity where the Whirlwind Artillery Gunners were stationed in front of Guisui Castle where Dong Bong-su had gone out.
He also exterminated the rats hiding in supply goods and such, and boldly killed soldiers who clearly showed signs of having contracted the disease. Moreover, he ordered all living soldiers to immediately bathe.
The disgusting smell of rotting corpses overflowed throughout the encampment, but as already promised, Li Zi-song helped with everything Dong Bong-su had requested. He even allocated the 5,000 gunners who operated the Whirlwind Artillery under Dong Bong-su's command.
Now Dong Bong-su had become a general leading 1,000 mercenaries and 5,000 artillerymen.
He kept his Status Window open without closing it. This was to respond urgently if even the slightest change occurred in the Status Window. While doing so, he immediately implemented the work he had conceived during the past several days coming here.
"Immediately disassemble all the Whirlwind Artillery."
If Li Zi-song had been present at this place and heard Dong Bong-su's order, he would have been horrified. Dong Bong-su, who they thought would use the Whirlwind Artillery to attack the castle walls, was disassembling the Whirlwind Artillery? As a commander, it was behavior difficult to readily understand.
However, Li Zi-song was currently overseeing the work of withdrawing the position backward, and at this place there were only Dong Bong-su and the 700 mercenaries accompanying him—about 300 had fallen into combat incapacity due to the disease on the way here—and the Whirlwind Artillery Gunners who had to operate the Whirlwind Artillery.
Although the Whirlwind Artillery Gunners couldn't understand at a glance, they didn't disobey Dong Bong-su's order. After all, soldiers had no choice. They were just soldiers who had to do what they were told and, if not told, must not do it even if they died.
Thud. Shrrrk. Thud. Shrrrk...
The area was bustling for a while with the sound of joints being loosened and each part being disassembled.
Since the Whirlwind Artillery itself had been assembled here, and the Whirlwind Artillery Gunners who specialized in it were doing it directly, the disassembly work was all finished before long.
There were now 100 Sky-piercing columns and wooden beams, along with various components and ropes connecting the two.
Dong Bong-su again ordered them to move all of those things to a place much farther from Guisui Castle. Though they couldn't tell why he was ordering such a thing, the gunners and mercenaries faithfully carried out his command.
The work was quickly finished, and Dong Bong-su immediately began the next task.
"From now on, watch carefully what I do and reassemble these items in a new way."
Dong Bong-su said that and immediately went into action without even hearing the soldiers' reply. Right now, time for him was like the fuse attached to a bomb. The biggest problem was not knowing the bomb's power or the fuse's length.
Since he didn't know when it would explode, there wasn't a moment to waste.
Thud. Slip. Clack...
By Dong Bong-su's fast and precise touch, the Sky-piercing columns and wooden beams were mechanically woven together. The item that had been assembled dozens and hundreds of times in his head over the past several days was rapidly taking shape.
It was an item that looked considerably more complex than the Whirlwind Artillery. Rather than simply driving and fixing one pillar called a Sky-piercing column into the ground, he organically connected several pillars at diagonal angles and fixed them to the ground, then attached the wooden beams vertically where the ends of the pillars met. He also overlapped two wooden beams instead of one, making it much larger and sturdier than the existing Whirlwind Artillery's wooden beam.
Critically, the difference between the Whirlwind Artillery and the item Dong Bong-su was making was that at the end, instead of connecting 40-50 trailing ropes, he attached a large basket. Dong Bong-su devoted particular effort to making that basket more than anything else.
As the apparatus gradually took shape, only then could the Whirlwind Artillery Gunners roughly guess what Dong Bong-su was making. Though they had never directly seen such a thing, the principle was easy to understand at a glance.
Unlike the Whirlwind Artillery where 40-50 people pulled ropes at once and used that force to launch stone projectiles, that item would fill the basket with objects like stones and use the force of dropping them to rotate the wooden beam and launch stones. They had seen many similar items back home. The water wheels in every village operated on a principle similar to that.
Thud. Slip. Clack...
If there existed beings called divine craftsmen, wouldn't they look just like that?
The Whirlwind Artillery Gunners could only stand there with their mouths agape, watching Dong Bong-su make 'some kind of machine.' Setting aside the amazing dexterity, the strength to bind and tighten wooden beams reaching about six meters alone was something they couldn't even imagine.
Thud. Slip. Clack!
Exactly half an hour.
That was the time it took for Dong Bong-su to assemble that thing, the 'trebuchet,' alone. He tied the final knot by pulling hard on the end of the rope, then looked around at the Whirlwind Artillery Gunners and said,
"Did you watch carefully?"
"..."
The Whirlwind Artillery Gunners still only had their mouths open, unable to answer easily.
"I asked if you watched carefully."
Dong Bong-su's characteristically low voice spread throughout the area again.
Only then did the gunners come to their senses and give a proper answer.
"Y-yes...!"
Dong Bong-su looked around at the senior gunners surrounding him one by one and spoke slowly yet clearly:
"I'm giving you exactly thirty minutes from now. After that, if even a single wood chip is lying around this vicinity, you will all die."
Gulp.
Someone among the senior gunners who heard Dong Bong-su's words swallowed dryly, and that became the signal.
Thud. Shrrrk. Clatter…
The trebuchet assembly began in earnest.
Trebuchet.
A catapult widely used in the medieval West of that other world. This was the siege weapon that displayed the greatest power until cannons using gunpowder were developed.
Compared to the Whirlwind Artillery that launched stones by human power, it boasted a range of as much as 3-4 times greater, and the weight of stones it could throw was also much heavier. Since it was mechanical, its accuracy was also very good.
Perhaps there were similar items in the Central Plains as well. But he couldn't be certain. Seeing that they were still using Whirlwind Artillery in this frontier battle, either they hadn't developed into such sophisticated devices, or early-form cannons using gunpowder were already being used within the Central Plains.
However, there was no reason for Dong Bong-su to consider such things. Such things weren't here right now, and he had never seen them once in the past year's harvests. If so, it was the same as them not existing.
To carry out what he planned, he needed a siege weapon with a much longer range than the Whirlwind Artillery. So he chose the most primitive form of trebuchet. It was the best option he could make as long as he couldn't create gunpowder weapons.
The trebuchet Dong Bong-su made looked very sophisticated at first glance, but in reality it wasn't that complex. The original trebuchet had pulleys attached, but Dong Bong-su deliberately omitted that part. If pulleys were included, the device's shape would become very messy. Of course, with pulleys, raising the counterweight would become much easier.
On the other hand, the device would become complicated and the assembly time would take long. In his view, using the manpower here or the mercenaries' strength, pulleys weren't particularly necessary. Unlike ordinary people, those who had learned martial arts could combine their strength to raise counterweights reaching several hundred kilograms or even several tons without difficulty even without pulleys.
That didn't mean he made it roughly at all. Every part except the pulley section was precisely calculated.
Over the past several days coming here, Dong Bong-su had thoroughly conceived the trebuchet, and he also had its range and form clearly drawn in his mind. Even if Li Zi-song hadn't handed over command of the Whirlwind Artillery Gunner unit to him, he had intended to move the mercenary corps separately and cut down trees from the Yinshan Mountain Range around here to make this item.
Thud! Thud!
The disassembled Whirlwind Artillery components were rapidly transforming into trebuchets. Since they were completely basic forms of trebuchets, it really didn't take long to make them. Just as Dong Bong-su had proclaimed, after thirty minutes passed, 32 trebuchets had been created. Whether because they didn't want to die, the gunners used methods like fitting in wood pieces whenever they found even slightly insufficient parts, utilizing every last small wood chip.
When all the work was finished, Dong Bong-su went around one by one examining the completed trebuchets.
There were no major problems. Slightly inaccurate parts were visible, but right now he didn't have the luxury to nitpick such details. He judged that as long as they operated properly, there would be no particular difficulty in carrying out the plan.
Having finished checking the forms, Dong Bong-su checked whether the direction aiming was done properly. However, since they had assembled them targeting Guisui Mountain Castle from the beginning, there wasn't much need to newly adjust the direction. Unlike the Whirlwind Artillery, trebuchets couldn't easily adjust direction, so when first assembling, the direction had to be well set like this. There were slightly askew parts here and there, but when Dong Bong-su exerted strength while using the skill [Circulating Energy], he could adjust the direction to precisely face Guisui Castle without much difficulty.
When that task was finished, Dong Bong-su immediately began transferring the round rocks brought to use as projectiles into the baskets attached to the ends of the trebuchets' wooden beams. Each projectile seemed to weigh roughly 2-3 kilograms. When calculated based on the basket's size, it seemed hundreds could be loaded. Then the total weight of the counterweight, including the basket's weight, would easily exceed several tons.
If the potential energy generated when a counterweight of this degree soared high into the sky then fell to the ground was entirely converted to kinetic energy...
'It's sufficient.'
Having finished setting up the trebuchets, Dong Bong-su turned his head to the side and looked at the black mound rising distantly in the distance.
Whiiish—
When the north wind blew, the smell the mound emitted spread all the way here. Though they were over 100 meters away, that smell was so nauseating that everyone except Dong Bong-su frowned.
The black mound.
Its identity was precisely the pile of corpses of soldiers who died from the Black Death. The mound was still continuously expanding its territory, the reason being that soldiers were ceaselessly carrying corpses there.
While the mercenaries and gunners all contorted their expressions looking at that, Dong Bong-su indifferently tossed out a remark:
"All preparations are complete."