Subtraction

"Mm, we could imagine that Thorn Flower's Royal Capital must have been enormously vast.

To use a magic array to protect the entire city, that array must have integrated some Space Magic. At the same time, as the defensive magic around the Royal Capital, its strength could not have been low.

And it was clearly marked here as unbreakable at Epic Rank.

And the enemy we could identify now was an alchemist, with an undead army under his command.

From what he had done so far, we could infer that he was still wary of Hui Dun City. That meant that, with his strength, he could not completely crush everyone in Hui Dun City.

And I remembered that the strongest person in the city was you, Headmaster Adolf. From what I saw, your strength was at most at the peak of Platinum Rank, so that alchemist's strength should not be too far off.

Then, with my current abilities, I could streamline this defensive magic array so that it only covered an area the size of Hui Dun City. Its defensive power only needed to reach Platinum Rank."

Chen Cheng voiced his idea. Adolf and Pembez exchanged a glance, then agreed to Chen Cheng's proposal.

"But even if we followed what you said, this magic array's rank is too high. There are many things inside it that Adolf and I cannot understand. Where should we begin?"

Pembez did not shy away from admitting his ignorance and directly asked Chen Cheng.

Because he was certain that since Chen Cheng had proposed this suggestion, he must have a solution. Though it seemed somewhat crazy, because Chen Cheng's reserve of knowledge was clearly less than his.

Yet this was not a problem for Chen Cheng.

Although he was inferior to Pembez and Adolf in magical knowledge, when it came to cognition, he was not bragging when he said that no one here could surpass him.

After all, in his previous life, he had been one of the nation's top researchers.

When researchers obtained a failed result and could not find the corresponding theoretical basis, they would use a crude method.

They would use their shallow knowledge to distinguish what function a failed section corresponded to, then directly remove that entire section.

That was right. The subtraction Chen Cheng wanted Pembez and Adolf to perform now operated on exactly this principle.

Here, Pembez was a Space Magic mage. There were some Space Magic components on this magic array diagram that exceeded his understanding, and he could not comprehend them.

But none of that mattered. He only needed to distinguish the spatial modules of the magic array. Then, every section that exceeded his understanding could simply be discarded, and what remained would be Platinum Rank spatial sections.

Given the size of Hui Dun City, Platinum Rank spatial sections would surely be more than enough.

And after streamlining it this way, the remaining magic array patterns would all be things Adolf and the others recognized. Even if they needed to be dismantled, it would save far more time and effort.

Moreover, Chen Cheng believed that this magic array system, already tested by time, would be hundreds of times safer than the completely untested magic array they had proposed before.

And he could use his Variable Magic to link together the sections that had been cut away. As long as the passage of Magic Energy could be ensured, it could operate safely.

The maintenance effort required would also be far less than before.

When Pembez and Adolf heard Chen Cheng's theory of subtraction, they found it difficult to accept at first. But they were, after all, geniuses of this era, and soon felt that there was nothing wrong with what Chen Cheng had said.

The streamlining work quickly began.

Meanwhile, Tofis, standing at the doorway, was dumbfounded. He did not know why Headmaster Adolf and the others were listening to a slave's opinion, but Wisdom Shield had no mind to explain anything to him now.

"Tofis, immediately go door to door throughout the city and conscript all male citizens. At the same time, go to the armory and take out bows and arrows to arm them.

Also, send people at once to transport every resource reserve from the storehouses to the academy. I, Komo Huidun, hereby issue a summons in the names of Prince Komo and Earl Huidun. Go quickly."

Tofis immediately accepted the order and left.

Very quickly, news of the alchemist and the undead legion under his command spread across the city like wildfire. The students studying in the academy and the instructors teaching there were swiftly gathered by Adolf as well.

The senior students preparing to graduate and head to the Royal Academy in the Royal Capital for further study, along with their instructors, all had to act. They used their magical knowledge to help Adolf inscribe the magic runes of the streamlined and dismantled defensive magic array.

The middle-year students were assigned to the city walls, where they could serve as small-scale magical support units and wounded-soldier treatment units.

The lower-year students had to serve as assistants, preparing the Mithril used by instructors and senior students to inscribe magic runes, as well as moving the Magic Crystals stored in the academy.

Outside Hui Dun City, birds could already be seen taking flight in alarm from the distant forest. Then, a black mass of skeletal undead poured out from the woods.

Among those Undead Skeletons, Undead Knights could be seen holding giant axes and riding undead horses.

When the soldiers in the watchtowers on the city walls saw the undead, they immediately rang the warning bells. The soldiers on the walls and the conscripted citizens holding bows stared fixedly at the endless tide of Undead Skeletons.

There was no sign of them ever stopping. It felt as though every heart had been seized by an invisible hand, and silence as deep as death had already fallen over the city walls.

After that deathly silence came an endless spread of panic. The first to break were the conscripted civilians, and deserters immediately appeared among them.

But just as those civilians shouted that the world was ending, threw down their bows, and fled backward, Torey, Wisdom Shield's knight commander, drew the sword at his waist and directly cut down every fleeing civilian.

"If anyone retreats again, this will be his fate."

Torey held his sword in one hand, blood from the people he had just killed splattered across his face, matching his icy gaze.

The panicked civilians were quickly frightened into silence. They could only tremble uncontrollably as they stared at the endless army of Undead Skeletons.

Seeing the sea-tide-like Undead Skeletons, Torey's heart sank straight to the bottom. He truly did not know whether Hui Dun City could hold on.

But when he thought of the oath he had made before Wisdom Shield, he clenched the sword in his hand. Even if he died, he would die on the road of charging against the undead.

Just when everyone thought the Undead Skeletons were about to attack the city, they suddenly discovered that the skeletons had split their forces.

Under the command of the Undead Knights, the Undead Skeletons began dividing toward both sides. The Church of Light's knight commander and Torey, both experienced in battle, knew that the Undead Skeletons were preparing to surround the city.

It seemed that this time, they truly did not intend to leave anyone a way out.

This had become the shared understanding of everyone with battle experience.

Seeing the soldiers trembling with nerves, Torey knew they could not keep waiting like this, or those soldiers would collapse as well.

The Knight of Light commander, also a commander himself, understood this principle. Without needing to speak, the two ordered the mages to launch an attack first.

For a moment, the Church's Light Magic and the academy's elemental magic flew together across the sky. Thunderous explosions continuously rang out beyond the city, and countless Undead Skeletons instantly vanished into ashes under the pincer attack of elemental magic and Light Magic.

Seeing that grand spectacle of magic unleashed all at once, the soldiers and conscripted civilians lost their earlier tension.

Seeing this, Torey immediately ordered everyone to draw their bows and nock their arrows. Then, following close behind the magic, tens of thousands of arrows flew toward the Undead Skeleton Military Formation.

The arrowheads of those fired arrows were magical items mixed with Mithril. Though their rank was extremely low, they were sufficient when launched together against these Undead Skeletons.

Those two rapid waves of attacks directly tore large gaps through the Undead Skeleton formation, while also giving the city's defenders a shot in the arm.

Hui Dun City had been built against a towering mountain cliff, and its three city walls were no more than ten li in length. Although this attack had killed quite a few Undead Skeletons at the front, it was still only a drop in the ocean against the skeleton legions surrounding them on three sides.

These Undead Skeletons had been made from corpses that the alchemist had gathered from nearly every graveyard and mass burial pit throughout Huidun Territory. Their numbers were simply impossible to count.

At that moment, atop the cliff behind the city, the alchemist stood there holding his Magic Crystal ball, looking down over the entirety of Hui Dun City.

When he saw that his psychological tactics had been somewhat disrupted by two minor attacks, he immediately ordered the Undead Knights to begin their assault on Hui Dun City.

On the city walls, before Torey and the others could even catch their breath, the Undead Skeletons outside the city took out their skeleton bows under the Undead Knights' direction. Then countless skeletal arrows shot toward the walls.

Seeing this, Torey shouted for everyone to raise their shields and defend.

Soon, iron-bound shields nearly two meters tall were raised, directly forming a shield wall atop the high city walls.

Skeletal arrows came raining down with whooshes, striking the walls and shields with a clattering din.

The Light priests were also desperately casting Holy Light Illumination, a large-scale spell that dispelled undead power. Otherwise, under such a dense shower of skeletal arrows, the entire city wall would long have been corroded and collapsed by the undead power within them.

As time passed, wave after wave of undead arrows fell like raindrops. The Undead Skeletons' arrows seemed endless, and many Light priests began to suffer from insufficient mana.