The S-grade school in the capital was responsible for training the most powerful mages humanity would have. It focused on training them in the ways of fighting and ethics. Other classes, such as history, were taught only briefly, and passing them wasn't necessary.
Still, even though history was not directly useful in battles, knowing it could help one become wiser. The specialists at the school added the history class to the schedule once a month.
...
After taking a deep breath, the teacher started: "The northern calendar, like the southern, western, and eastern calendars, is based on the date of birth of powerful mages. The northerner's most powerful and famous mage, whom they considered their savior, was known as Mage Demon Crusher. He was a demon born with amazing talent who united the northern cities and cleared human areas of demonic presence"
"His accomplishments were immense; I believe that without him, northerners would have been wiped out long before the birth of master max. Still, even though Mage Demon Crusher was very powerful, his influence was limited to the north. The west, south, and east were separated from the north by the big demonic city in the middle. The demonic city was named the Tower of Death. This is the same big demonic city that Master Max eventually destroyed to unify humanity in the famous battle of liberation. After the destruction of the Tower of Death, Master Max built the great wall around the entire human civilization, thus providing a safe haven for us".
"The Tower of Death was long a target of human mages; Mage Demon Crusher himself eventually died when, after unifying the north, he later attempted to destroy the Tower of Death. It's said that he nearly succeeded, but the pureblood demon in charge came out at the last moment and killed him in one blow. The death of Mage Demon Crusher was devastating to the North. They fell apart immediately and split into many independent cities that all hated each other. Still, they all unanimously adopted the birthday of their hero as the starting point of their calendar."
"The north was less populous than other areas, but even then, it was home to millions of people. It was made of many different tribes that were glued together by the genius of Mage Demon Crusher."
"With Mage Demon Crusher's death, northern cities were left without a leader and returned to their previous tribal state. They were never really united; Master Demon Crusher just kept them together using his personal popularity, but with his demise, his influence disappeared immediately."
"The north was opposite to the south. The South was very united. It's not that its people were inherently different; it's just that they were forcibly integrated many decades ago. In the south, the cities were not based on tribes. The people of the South didn't see themselves as part of any tribe; they saw themselves as simply Southerners. This culture was one reason that the South was the strongest human front at that time."
"Even though the North was very disunited, they still collaborated together when they faced a demonic threat. Everyone knew that the biggest threat to them all was demons, so even though they hated each other, they still wouldn't fight each other too seriously. They never brought their mages into fights among tribes; at most, they would fight using ordinary armies."
"Humans at this time had little power to fight against demons; they could, at best, hide like mice in the shadows. They were not at all safe; it wasn't abnormal to have one human city per year destroyed by demonic forces."
"The most famous point of collaboration among the northern forces was known as the pit point. The natives of the time simply called it 'the site.' It suddenly appeared in the 56th year of the Northern calendar close to the ancient city of Northern Horn"
"The pit is a point of concentration of chaotic dark energy. Very little was known about it at the time. However, even then, they knew two things: first, that demons must never discover its existence; second, that it should not be touched; otherwise, it could cause a disaster."
"Today, It has been proven that pits are places where chaotic demonic energy's concentration is so high that it turns into one or more solid crystals. At the time, it was called the Big Dark Crystal, according to its appearance."
"Pits appear in random places, and the reason for their appearance is still not well understood. The research on them is very difficult. After all, these things are extremely hard to find; after the Great Wall was erected, pits no longer appear inside human territory. At the moment, we have no way to research them, first and foremost, because we don't know of any pit's location."
"The Big Dark Crystal itself is not useful for humans; however, it is extremely useful for demons. It can purify the blood of a demon. If used by demon-borns like us, it would corrupt our human blood and kill us at best or make us lose control at worst. Remember this, and don't even think of using it to increase your power."
"The appearance of a pit was a disaster for humans living in its vicinity. Demons instinctively knew of its amazing power and would rush to get it. It could attract thousands of demons and cause a disaster for all humans living around it."
"They collaborated with each other to keep it hidden for years. Still, eventually, around the year 65 of the Northern calendar, the demons of the Tower of Death found out about it. Their leader kept it a secret and sent loyal subordinates to quietly obtain it."
"The leader of the Tower of Death was not the only one who found out about the pit. Master Max also found out. Unlike many other humans, Master Max knew how to safely move the Big Dark Crystals, so he also sent a few of his powerful subordinates to go and get it."
"Even though the Big Dark Crystal was not directly useful for Master Max, he still didn't want to allow the demons of the Tower of Death to obtain it. By this time, Master Max already had plans of attacking the Tower of Death. The Big Crystal had the power to create a pureblood demon. The Tower of Death already had two pureblood demons; adding one more would have made destroying it much more difficult."
"In the end, demons obtained the Big Dark Crystal first, but Master Max's subordinates ambushed them. Unfortunately, the battle among demons and mages is very destructive. In the midst of fighting, the Big Dark Crystal was damaged and eventually blew up, killing two of humanity's best mages instantly. The rest all retreated."
"The Big Dark Crystal is extremely unstable; even one touch can cause it to explode. This is why the northerners only tried to keep it a secret and didn't try to bury it or take it out. If one lacks the skill, one shouldn't even think of getting close to the pit. Most demons naturally knew how to use it, but most humans don't."
"An explosion of a Big Dark Crystal would endanger everyone who lives in the radius of impact. The radius was very large, with most of the north in danger. This incident is what caused the famous zombie apocalypse disaster."
"Red toxic clouds appeared and were blown in all directions. Anywhere they passed, they left a trail of destruction. Any living thing affected by them turned into a monster known as a zombie, which has horrifying vitality and very high resistance to magical spells."
"However, Master Max should never be underestimated; he used the disaster to his advantage. He researched for weeks and finally invented a spell to control the zombies! In the meantime, he also sent most of his subordinates to go to the north and help them evacuate the area."
"After inventing the spell, he personally went north and gathered all the zombies. Then, he led them all to the Tower of Death"
"Zombies were natural enemies of magicians and demons; they were physically strong, very hard to kill, and especially resistant to magic. They were the perfect cannon fodder."
"One shouldn't underestimate the magnitude of the zombie army. There were hundreds of thousands of human zombies, tens of millions of animal zombies, and billions of insect zombies. They completely surrounded the Tower of Death from all sides; even the sky was full of zombie birds."
"Zombie birds are tens of times more powerful than a normal bird; even demons had problems dealing with them."
"Master Max and his subordinates hid in the midst of the zombie army and used them as a shield. In the end, the entire demon city and all the demons inside it were destroyed with very few human casualties. This victory completely cemented Master Max's position as the leader of human civilization. We all heard of this battle as the Battle of Liberation, where the Tower of Death, which separated humans from each other, was destroyed, finally paving the way for the creation of the Great Wall."
"Master Max destroyed the demon army and the monster zombies, hitting two birds with one stone. Truly admirable!" The old man sighed with praise; even though he had told this story many times, he could only sigh and admire Master Max's genius."
"The news spread, and soon, emissaries from various cities arrived and submitted themselves to Master Max. He became the uncontested leader in less than a month. The northerners were especially loyal to him; after all, they wouldn't have been able to run from the zombie disaster if it weren't for the help he sent. After a few years, they eventually returned to the north, but they remembered Master Max and were of great help to him later on."
"After the unification of human civilization, Master Max started his project of creating the big wall. Until now, the Great Wall was only aspirational; even if they had the resources, the Tower of Death in the middle was an insurmountable obstacle. However, after the destruction of the tower, human leaders started to take the Great Wall project seriously."
"Master Max worked for months and designed his famous wall design; he proposed plans for gathering resources; everyone trusted him, so even though it looked near impossible to gather that many resources, they all agreed and got to work"
"It took decades to gather enough resources to complete the Great Wall, but I'm happy to say that it was completed before Master Max's passing. He lived long enough to see the great and vibrant civilization he founded." The teacher sighed again and again, visibly emotional.
"Never forget the greatness of Master Max; he is the reason we can live in peace. Now, if anyone has a question, please ask," the teacher said.