Castle of Black Iron

“This is your final history class and my last class before retirement. After this class, I will retire officially…” the teacher said to the students at the beginning of the second morning class. Hearing this news, the whole classroom turned quiet. Even Zhang Tie could not imagine that this was the last class for the teacher. Since he entered the Seventh Male Middle School, he seemed to have gotten used to this gray-haired old man who would enter and leave the classroom quietly. He never thought that the senior would bid farewell to them on the rostrum. The moment the teacher delivered the news, even the fellows sleeping in the classroom seemed to become awake. They gaped at him and felt reluctant for his will-be retirement.

“Are you really going, teacher…” a guy in the front row poured out what the other students were thinking in their hearts.

“I am already very old, and I have also served Blackhot City for a long time. It’s the right time for me to retire!” The old man showed a friendly smile. “I know what you are worried about. As long as the city walls of Blackhot City aren’t broken by the alien forces, my pension would be enough for me to live the rest of my life in peace. And you guys are the ones who will ensure that the city walls will stand firm forever, not me. That’s why, whether I will live a peaceful life or not after retirement will depend on you! In today’s final history class, I will talk to you about my experiences and knowledge of what I’ve seen that is required to be a powerful man who can protect the human race.”

Hearing the final sentence, everybody’s spirit rose. All the students sat straight instantly and stared at this revered old man with reluctant expressions.

The old man was then silent. Pulling out a small, ordinary snail shell and two pine cones from his pocket, he passed them to the front row and let the students observe them one by one. After one minute, the snail shell and the two pine cones had been passed through the hands of every student. Nobody found anything special with them, including Zhang Tie who had thoroughly checked it for a couple of seconds but was unable to find anything.

“Do you guys notice anything special about the snail shell and the two pine cones?” the old man asked. Everybody shook their heads.

“You should know that the secret for the average human to become stronger is hidden within these ordinary things! We all know that people should always be trying to ignite their burning points to improve their strength, and we also know that human fighters are classified at different levels. Some people are LV 5, some are LV 6, some are LV7, and there are even some who have reached LV 10 or higher. However, who classified our fighters? Are those classifications made by the big figures in the Fighters Union?”

Zhang Tie was startled, as he had always thought that the standards were created by the big figures. It wasn’t made by them?

“Of course not, no one is entitled the right to create the standard in which billions of commoners and powerful figures pursue!”

“Teacher, then who made the standard?”

“The person who created it wasn’t a human being — but a god or the laws of the great universe!”

Hearing his words, the whole classroom became bustling.

“Those standards were not made especially for the human clan, but for everything in this universe. The snail shell and the two pine cones I have shown you also follows the standard, but you didn’t notice them!” Afterwards, the old man drew two patterns on the blackboard using a piece of chalk. One was a spiral curve that was similar to a snail shell, while the other was some crisscrossed lines that were similar to the pine cones.

Then, the old man turned around. “How many burning points do we need to ignite to become a LV 1 fighter?”

“One! We only need to ignite the Shrine burning point...” the students replied in unison. The old man then drew a square in the center of the square shell in a way that the spiral curve went through the two opposite corners of the square...

“What about LV 2”

“It’s also one. We just need to ignite the burning point on the tail bone of the spine!”

The old man expanded the pattern and drew another square of the same size.

“What about LV 3?”

“Just ignite two burning points on the spine!”

This time, the old man double the length of the side of the square.

“What about LV 4?”

“Three!”

“LV 5?”

“Five!”

“LV 6?”

“Eight…”

The spiral curve was gradually wrapped by squares with side lengths that increased proportionally. Finally, when the old man asked how many burning points needed to be ignited to reach LV 10, nobody in the class could reply. Fighters above LV 10 were an amazing existence that the horny students could not imagine at all. For them, the world of fighters above LV 10 was as far as the Catastrophe itself...

Instead of mocking them, the teacher wrote down a series of numbers —1, 1, 2, 3, 5, 8, 13, 21, 34… — along with their corresponding levels, 1 - LV 1 to 34 - LV 9. Finally, he turned around and looked at students with shining eyes. “Have you ever figured out a law among those numbers?”

After staring at those numbers for a while, someone finally realized. “Each number is the addition of the previous two!”

“What else?”

Looking at number sequence, something in Zhang Tie’s mind seemed to burst forth; however, Zhang Tie wasn’t able to figure it out.

“Why not divide the next by the earlier and figure out the law among them?”

As the horny students had learned the basics of math, they lowered their heads and started to calculate the results. The first result was 1, the second result was 0.5, the third result was 0.66666…, the fourth result was 0.6, the fifth result was, 0.625, the sixth result was 0.61538..., the seventh result was 0.619047, and the either result was 0.617647...

“Have you noticed that the numbers are infinitely close to 0.618?” the teacher poured out the truth, enlightening all the students. Yea, how could that be?

“To reach LV 1, one needs to ignite one burning point, while the human body has 33 vertebrae on the spine. When one ignites all the burning points on the spine, they would reach LV 9. Strict standards have been made for reaching each higher level. Likewise, you can calculate by yourself how many more burning points you need to ignite to become a LV 10 fighter. 55! Yes! What’s next? 89! The number would grow geometrically in a terrifying way. That explained why the higher the levels were, the greater the differences would be, and this sequence…” the old man turned around and pointed at those numbers on the blackboard, “...is called Leonardo Fibonacci Sequence, which was the Golden Sequence that contained numerous secrets discovered by a human mathematician named Leonardo Fibonacci hundreds of years before the Catastrophe. It contains the universal law and the law of the creator. Look at the spirals on the right and left of the pine cones. Have you noticed that the smaller one has 5 lines on the left and 8 on the right, while the bigger one has 8 on the left and 13 on the right? The numbers 5, 8, and 13 directly correspond to the Fibonacci Sequence. You can check the squares on this snail shell curve. You will then understand the relationship between this curve and this sequence of numbers — the Fibonacci Curve or Golden Ratio. The curve is the geometric pattern of this sequence. You can find this relationship on most living begins. If you take a look at nature and the things beside you, you will find more examples. For instance, there are two groups of spirals inside the flower disc of a sunflower, and the corresponding numbers are 34 and 55, 55 and 89, 89 and 144. Similarly, you can get the same result in roses and thistle leaves. After the Catastrophe, people discovered the secrets to practice cultivation from the underground ruins and realized that all the improvement and cultivation that the human race were doing were in accordance with the Golden Ratio and the Fibonacci Sequence. Even all other living beings evolve along this curve. As the curve and the number sequence is the reflection of the universal law, fighters that didn’t evolve in line with this curve and the number sequence would never be considered strong by the standards of all the humans and the powerful figures...”

Hearing the explanation, all the horny students had their eyes opened, including Zhang Tie. Previously, he only knew that he had to ignite different numbers of burning points to reach higher levels; however, he didn’t know why and had never put thought into it. Whereas at that moment, Zhang Tie finally understood that all the secrets were hidden in the universal law in the golden spiral and that number sequence.

“Teacher, what’s the highest level after LV 10?” raising his hand, Bagdad asked.

“Even now, nobody knows the answer to this question because what comes after LV 10 is one of the most confidential secrets in any place. Knowledge after LV 10 is top secret. The most important reason being that the golden number sequence is endless as it constantly develops and gets increasing closer to the perfect number, 0.618. It has been less than 900 years since human beings stepped onto the road of cultivation in accordance with the golden spiral and have started to explore the treasures within their own body. In contrast, the universe has already existed for tens of billions of years. This means that we human beings have just started on the golden spiral. Before the Catastrophe, people were always proud of themselves. At that time, they treated themselves as the lord of the universe and everything else. However, after the Catastrophe, humankind started to realize that the human clan was just a trivial member among the numerous clans in the vacant universe and the Kun’ang Continent. The human body and human civilization might even have regressed instead of further evolving over a long period of time before the Catastrophe. When it was no longer able to regress even further, the Catastrophe and the Star of God arrived and all the rules were rewritten. People also discovered the secrets hidden within their body that would aid them in survival, leading them back onto the path of evolution. The Age of Black Iron — the end of the past and the beginning of the future...”

In the final history class, the teacher opened an unprecedented window for them which really broadened their view. For the remaining time in the class, all the horny students manually calculated the numbers in the Golden Sequence.

1，1，2，3，5，8，13，21，34，55，89，144，233，377，610，987，1597…

Zhang Tie gaped when he got to the 17th number in the Golden Sequence. He couldn’t believe his eyes when his line of sight fell onto the last seven numbers. “Is this the number of burning points needed to be ignited after LV 10…” Zhang Tie was really shocked.