Catching the disease didn't mean unconditional death.
Bubonic epidemic, septicemic epidemic, pneumonic epidemic, and so on.
There were various types of disease with different fatality rates. Since Dong Bong-su wasn't a medical student, he didn't know about such things in detail. He only knew a bit roughly.
Perhaps.
'I might survive.'
But thinking differently, perhaps he could also die. There were records that starved, unhealthy people with weakened immune systems died first, but that was merely a record. Those who didn't live in that era couldn't know all of what it was actually like. Now was the actual situation, and he was already contaminated with the disease bacteria.
In other words, some probability of death had arisen. No, was that probability really small? No one knows. Dong Bong-su was human too. Any human could suddenly die at any moment.
Perhaps he had caught the most serious disease, and the possibility of survival was already slim.
However, he excluded that possibility for now. In such a case, he could only leave his life to luck, so it had no value to consider now.
After excluding that case, survive by doing his best. That was still his supreme task.
Then what should he do to survive unconditionally?
'It's simple. I must cure the disease. Then how?'
In Dong Bong-su's head, one certain method flashed by. In this uncertain world, there was no treatment as certain as that.
It was...
'Level up!'
Though the system couldn't detect the existence of bacteria, it recognized it as poison. Then that meant it could remove it. If he achieved a level-up to 31, he would recover from status abnormalities at the same time.
Whether the cause of [poisoning] was disease or another bacteria, or truly an unknown poison, wouldn't matter to the system. The moment he leveled up, the system would simply eliminate what became the source of status abnormalities in Dong Bong-su's body, or if that was impossible, it would eliminate the disease bacteria even by reconstructing his entire body anew.
The solution emerged. More precisely, only the solution emerged, and various problems still remained.
Dong Bong-su continued thinking while retracing knowledge he had piled up beyond that memory.
The incubation period of disease was as short as a few days, as long as two weeks to a month. He had to level up unconditionally during this time.
Then what methods could level him up?
Dong Bong-su raised his head to look at the mercenaries. His eyes were hidden even deeper by bangs grown long, so the mercenaries couldn't read his expression at all. If they could have seen those eyes, the mercenaries wouldn't have dared look straight into them. Because those were the eyes of a predator determining whether or not its belly would be full if it ate these things.
Dong Bong-su scanned the surrounding mercenaries one by one.
'About a thousand such mercenaries, then...'
"It would be difficult."
"...?"
The mercenaries couldn't understand what he was saying. Much less that their lives had been saved by that single statement.
Dong Bong-su judged that leveling up would be nearly difficult even killing such mercenaries now. He intuitively knew that even killing everyone here wouldn't amount to much experience.
He had to find stronger enemies that gave more experience. And such enemies in a nearby place.
He had already come very deep into the grasslands. If he returned to Datong at this point, the disease might break out and kill him in the meantime. Moreover, there were almost no strong people in Datong who could help Dong Bong-su level up. At best, only the blacksmith of Eight Directions Armory. Dong Bong-su couldn't guarantee whether he could kill him or not. In the worst case, the blacksmith might be far stronger than him. Then returning to Datong wasn't a very good option.
If he couldn't return to Datong...
'I must find another place densely packed with enemies having large experience in the near future.'
Before long, Dong Bong-su could think of one place.
That place was...
Crunch crunch.
Then he heard in his ears the somewhat off-kilter sound of horseshoes stepping on sand. The mercenaries don't move around on horses. And that sound was one he had heard once before. Considering that the sound pattern wasn't much different from what he heard then, it was likely the same horse and same person.
'Li Zi-song's messenger.'
Certainly, as Dong Bong-su thought, the one who appeared then was that messenger he had seen at Tianchi Village. This time, unlike last time, he came to a place slightly away from Dong Bong-su and dismounted.
Then he walked up to Dong Bong-su.
The messenger slightly bowed his head, took out a letter from his bosom, and held it out to Dong Bong-su.
"A message from the Commander."
Dong Bong-su immediately received and unfolded the letter. The letter contained writing as short and concise as the order given when attacking this place.
Come to Guisui.
Dong Bong-su rolled up the letter again and handed it to the messenger while speaking.
"What became of Liangcheng?"
"It fell yesterday."
The messenger's tone was respectful as if to a superior. Not only because the mercenary captain called Ear Ghost before him had achieved merits far exceeding ordinary generals. It was because of Dong Bong-su's unique emotionless atmosphere that unknowingly made people shrink.
Hearing the messenger's answer, Dong Bong-su turned his body toward where the military tents were while speaking.
"Go and tell him. Since I've eliminated Manhan Mountain, I'll go to Guisui immediately."
Strictly speaking, a few Northern Ghosts still remained at Manhan Mountain, but there was no need to deal with them. Anyway, they had already fallen prey to the disease.
"Understood. I will convey it to the Commander."
The messenger put the letter back in his bosom and mounted his horse.
Then Dong Bong-su's level voice reached him again.
"Did soldiers enter Liangcheng?"
At Dong Bong-su's question, the messenger paused and answered.
"...Yes. Why do you ask?"
"Nothing."
With those words, Dong Bong-su headed to the military tent where the mercenaries were gathered. He thought again while walking.
Apparently Li Zi-song's large force had entered Liangcheng, which had probably been rife with disease from long ago. That meant Li Zi-song's army was already finished. At this point, what Li Zi-song could choose was either retreat or attack Guisui even amid the epidemic's rage.
And Li Zi-song seemed to have already chosen the latter. This case too could be divided in various ways, but it was meaningless to Dong Bong-su.
What mattered to him now was heading to Guisui. If Li Zi-song had chosen the former...
Dong Bong-su would have killed all the mercenaries here and headed to Guisui alone. Because that was the side with even a thread's worth of higher possibility of survival.
Already nowhere on this grassland was there a place to avoid the shadow of the Black Death. Then what should he do?
Isn't it obvious?
Dong Bong-su would walk that shadow himself. To do so, he headed to Guisui.
In his head, a passage from a book he had read before was automatically replaying.
「Day and night, hundreds of people died. ...Before long the entire land will be covered with graveyards. I, Agnolo di Tura, also buried five children with my own hands. ...Witnessing these countless deaths, people believed the end of the world had come.」
The book's title was The Epidemic of the End Times.
2
***
"Fire!"
Following the officers' orders, all Whirlwind Artillery Gunners pulled the trailing ropes (the rope that serves as the cannon's switch) with all their strength. Then the upper part of the wooden beam (the pillar that launches projectiles from the cannon) rose and rocks were fired.
Boom! Kaboom!
The rocks flew vigorously and mercilessly pounded Guisui's walls and gates.
Crumble...
Traces of slight cracks formed on part of the wall and stone dust scattered. But it was only a very small amount. Looking at the whole, Guisui Castle still stood firmly in place like a thousand-year boulder without budging.
The gates needed no further mention. The Guisui gates made of steel plates over three inches thick were intact from any perspective. Perhaps because Guisui Castle itself was a semi-mountain castle slightly perched on a hill, the catapult stones didn't reach well, which made it more so.
"Commander! At this rate, we don't know when we can break the gates."
"Keep firing! No matter how much of an iron lump it is, it will break someday."
"However, Commander! An epidemic is already rampantly spreading in the camp. Even now if you retreat..."
"Retreat? Did you just say retreat? Where to? Exactly where are we retreating to?"
"..."
Adjutant Dang's answer broke off.
Li Zi-song's words were right. They had already lost the place to return to.
A few days ago when attacking Liangcheng, about 20,000 cavalry had appeared close to the rear of Li Zi-song's main force. At first, Li Zi-song thought they were reinforcements coming to save Liangcheng. So he temporarily lifted the siege of Liangcheng and reorganized the formation for facing the cavalry.
But the moment Li Zi-song's troops finished battle preparations, the cavalry suddenly turned southeast and disappeared.
That direction was, needless to say, the path Li Zi-song and his 50,000 troops had walked until now.
At the end of that path?
Of course, without question or further mention, Datong was there. In other words, the enemies had gone to Datong Military Command.
Seeing this, several officers thought supply and rear support would be cut off, and ultimately Datong might fall. Therefore, some generals even petitioned Li Zi-song that they should retreat immediately.
However, Li Zi-song had dismissed that opinion outright. Though only farmer-soldiers remained at the command defending the castle, Datong was the north's greatest fortress and not an easily collapsible place. In addition, retreating now would be admitting his failure, so he could even less do so.
The opportunity given to him was only this one time. Retreat was like throwing away that opportunity, which meant returning to Datong was an action and decision no different from holding a blade to his own neck.
Therefore, Li Zi-song proceeded with the attack on Liangcheng and finally succeeded in occupying it.
But...
That was now strangling the entire expedition force's necks.
Upon occupying Liangcheng, they found a serious epidemic had spread there, and before they could do anything, the epidemic transferred to the occupying forces...
The jet-black epidemic.