The walls are built like the shells of an egg around the precious yoke. The precious yoke in this case is the Purple Flower sect.
A single shell is strong in its own, but more eggshells are built around the egg in order to reinforce it. So the more walls there are, the more difficult it will be for the egg to break.
The job of the people of the Purple Flower sect is to reinforce their sect. This job is very important because if the war goes badly, the grounds of the sect will be the final battlefield.
But despite how important this job is, only the people of the Purple Flower sect are allowed to do it. They are not allowed to receive any helpers in order to avoid the infiltration of enemies.
For the Purple Flower sect, only exit is allowed, not entry. And this exit will only happen when the war is about to start, and they have to join the battle and defend the walls.
In the meantime, it is the job of the people of the four sects to build the walls and fortify them. To be exact, it is the job of the people of the three sects to build the walls, while it is the job of the people of the Blood Skull sect to enhance the walls with formations.
This distribution of work is because only the people of the Blood Skull sect are familiar with formations. They are the only ones who can do the job, so they were assigned to do it.
The Blood Skull sect specializes in raising plants, forging artifacts, and building formations, while the people of the Sword Way sect deal with forging weapons. The Sword Way forges weapons, not artifacts. And the weapons that they forge are swords, so their skill set is further limited.
The Beast Training sect specializes in raising beasts and helping them grow and advance. The Black Bones sect deals with raising corpses. Finally, the people of the Purple Flower sect work with poisons.
All of them use formations to protect their sects, but they paid people to set them up, and they also only follow the manual and can't repair or change the operation of their formations. This lack of understanding of formations is why it was so easy for Sword Flash to infiltrate their sects.
No one else can help the people of the Blood Skull sect in building the formations for the fortifications. But this doesn't mean that the Blood Skull sect will be responsible for most of the defense. In fact, it means the opposite.
After the patriarchs of the five sects distributed their work, it was decided that the job of the Blood Skull sect was to build formations and maintain the operation of the formations during the war. Meanwhile, the other four sects would be the ones who risk their lives defending the walls and fighting off the invaders.
So the people of the Blood Skull sect get to do the easiest and safest job. This is despite the fact that they are the strongest sect.
This arrangement was why the patriarchs of the Blood Skull sect decided not to force anyone to participate in the war. After all, they didn't need to risk the lives of the people in their sect, so they didn't care about having the advantage of numbers.
This wasn't the case for the other four sects, though. The four sects had a minimum number of people who must man each wall. So the more walls that are built and fortified with formations by the Blood Skull sect, the more people the four sects have to send to defend those walls.
Everyone's job and duties have been clearly outlined. So when Arthur and the others arrived, there was no confusion about their duties and what to do. They went directly to their posting and began work immediately.
The golden core elders were the ones who would do most of the work in setting up the formations. But each one of them had a team of foundation establishment Junior elders to assist them.
Every golden core and elder also knew what formations they would build, how to build them, and how to align them. This was a good part of what they discussed during the tactics section of their last council meeting.
One of the decisions they made during the discussion of the tactics was to use water and ice attacking formations. This decision was made to counter the Red and Blue Life Fire of the Red and Blue Fire sect.
While the people of the Blood Skull sect worked on the formations, the people of the other sects didn't remain idle. They worked hard to build strong walls. Then they filled in the gaps between the walls and were forced to defend them.
The walls were not made with dirt. They were built with bricks that had been hardened into rocks. This made the walls physically durable and their surface smooth for runes and formations to be inscribed on them.
As for the forces that were used to defend the walls, they consisted of beasts and corpses. The beasts and corpses were not kept together. They had different sections assigned to them. The area between the walls was packed full of them, while the cultivators themselves would stay on the walls.
Moats were also built in the areas between the walls. They were built in the areas where only the corpses were allowed to stay. This was because the moats were filled with poison.
The preparations for battle continued like this for many days. Even before the fighting had begun, the city outside the Purple Flower had been destroyed, and the area around the sect had been dug up and modified.
The Purple Flower sect became unrecognizable even to the people who were most familiar with it and had lived their whole lives in it. But as different as things had become, it was expected that there would be more changes when the war started.