"Huh?" The whole class exclaimed at the same time. ‘There's still more?’

"When I was younger, I interested myself a lot in anatomy. Mainly to be able to strike the vital points of my opponent with the most accuracy possible. But that’s not the point. I’m sure you all perfectly know about the organs and muscles, such as the heart, and of course, the brain, right?"

"I’m going to tell you about the latter for a moment. Nobody really knows all the mysteries contained in the brain. But it’s undoubtedly the most important part of our body. Some also say that it is where the soul resides. Well, at least, we can be sure that it’s the embodiment of our spirit and mind."

"The brain subconsciously manages our body at every time of the day. In a sense, we can't use our brain at all. We are seeking help from it; would be a better description. Now, the reason I'm telling you this, is because the brain is doing something to your bodies since birth," Arima declared and his students became earnestly curious.

“From where I come from, people started saying we could only use ten percent of our brain’s capacities. Of course, that’s only an urban legend. It’s not true. In fact, our entire brain is used and works all day to manage different things.”

"But, there’s one undeniable thing, we can’t control our brain. And we also can’t be sure if all of its capabilities are operated to their maximum capacity. In the end, most of it is subconscious while our actual consciousness is most likely just a small portion of the brain. This brings me to the main topic; our physical-output threshold.”

"Our body usually can only use around 50% percent of its total strength because of a restraint the brain imposes us. Of course, that's because if the body is forced beyond that limit, it could harm itself in the process. Truthfully, you can withstand 100% of your strength if your body is strong enough. Then, after that, if you could go higher what would happen? 120%? 150%? 300%?" He asked and the people in the room started making their imagination work.

“Obviously, that’s a bit ludicrous. The way our strength is limited is through our varied Motor Units. The secrecies of our muscles and fibers. That’s why my technique relies on overheat. Basically, you’d give energy to your muscles and force it to go over its limits. The energy is not definite. Mana is an option, as well as life force, and even things like ‘internal force’ which still needs to be debunked if it really exists.”

The more the students thought about it, the more shocked they became. If all of this was true, then even if they had to suffer injuries from the downside, it was more than just worth it. A jump from 50% to 100% was huge.

Arima illustrated everything with the hologram. The figure pictured had his muscles suddenly contracted and his heartbeat increased along with his blood pressure. "This is one hundred percent," Arima commented.

Then, after that, the figure's muscles contracted even more and the veins pulsed. Even the organs started to tighten and the body temperature also raised.

"Around 125%, and let's stop here," Arima said. "From what I experienced, this limit break also includes the maximum limit of mana you can concentrate at once," he declared and as he spoke, a blue glow flowed through the veins in the projection and then it started expanding before totally covering the figure. It even exited the latter's silhouette.

"Well, if you try to punch in that state," Arima paused and snickered. "Say goodbye to your hand. Make sure to think through before employing this. I recommend you to only use 100% while training."

The students strongly nodded and light illuminated the room afterward.

"That's all for today. Tomorrow, I'll bring you all to practice outside and personally guide you. Now, time to leave the place for the next period.”

Arima continued to teach about physical enhancement until noon, where he decided to go eat at the cafeteria of the school. There, he found out that the food served was really high quality.

"As expected of the biggest school on the planet," he remarked and inspected his meal. He was eating with Lanya and Night at a table. There was no one around. It wasn’t that people feared them, but more like they weren't courageous enough to accost them.

"Hello again," a voice resounded in Arima's ears as he was slurping his pasta. He looked up with his mouth still full and noticed Velvet gazing at him with a smile on her face. He swallowed and stared back at her.

"Yes, hello," Arima answered with a courteous smile and Velvet's expression twitched.

‘If you are so polite, why the heck did you leave me like that this morning?’ She complained inwardly and sighed. She put down her tray on the table and smiled at Lanya. "I hope I'm not disturbing your meal."

"No, it's fine," Lanya shook her head and replied. Night was feasting on his meal without sparing Velvet a glance.

The latter turned toward Arima and snapped her fingers. She conjured a soundproof barrier to keep this conversation private. The students around were looking at them in wonder. Trying to guess what it was about.

"I'll be frank with you. You said that you will educate a class to participate in the ranking competition, right?" Velvet asked with a serious expression. Her expression had lost most of its gentleness and her words were slightly more familiar.

Arima blinked and nodded. "Yeah."

"In that case, I'm sure you’re aware that at the end of that event, the representative teachers will also compete against each other. I wish for you to step out from that last part. There’s simply no way any of us teachers can beat you. I heard rumors; that you fought with the Demon King, Raal Zalda, and won. Also, from the princess herself, your soul beast is apparently strong enough to threaten the city."

Arima was a bit surprised. Velvet's forced gentleness and politesse weren't meant to trick him or anything. It was just her personality, and she was trying to hide it in public. Her revealing it to him was the same as proving her sincerity.

Arima mused. "Fine… I never intended to participate in it anyway."

"Huh?" Velvet was stunned. "Why?"

Arima smiled and patted Lanya’s shoulder. "She’s the one who'll fight in my place. She needs some experience, you see."

Velvet scanned Lanya with her eyes. "…She's only at the late ninth level. Although I'm just at the early tenth, there's still a huge difference. I don’t want you to step down because I’m afraid. I just wish for a fair battle."

"Don't worry. She has an inheritance and was personally trained by my soul beast. She is on par with you," Arima casually answered. Velvet's eyes widened and a flash of surprise flashed in them.

She looked at Lanya one more time before nodding. "If you say so, then I have no complaints. Let’s do our best for the competition then. I’ll see you then," she declared and left the cafeteria.

"Wait… Why am I fighting again?" Lanya asked after a moment of silence and Arima started laughing.

***

At the end of that day, the information about Arima's lecture freely spread across the whole city. Everyone was surprised by the limit-break technique. But what alarmed them the most was the Soul Contract Arima came up with.

The magic circle he had given to his students landed in the hands of many people already and there were already some idiots that tried to contract more than one soul. After their deaths, nobody ever tried again. People always needed absolute proof to stop doing something dangerous.

When the royal family heard about that, it was without saying that it shocked them to the core. When they thought about it, they knew nothing about Arima. He had just appeared out of nowhere a few months ago and that was the first time someone ever heard of him.

Now, that guy casually gave away those techniques that seemed to be ahead of their time.

From that day onward, the planet changed drastically. The Soul Contract became popular all around the world and people's strength skyrocketed.

It was also heard that a dwarf had created innovative machines with something that he called steam power, which brought a large change to the science.

Then there was Raal who remembered Arima's bizarre weapon and decided to try reproducing it, which then became a phenomenon.

But all of this is part of another story.

***

The next day, at every period, Arima brought his class to a barren land to serve as a training ground. There, he taught them how to break the limit established by their brains.

It was actually pretty simple, in a world of magic at least. You just needed to interact with your brain with mana and then create a sort of telepathic link. That link was a soul magic impulse basically ordering the brain to cut the limit until a certain extent. Arima had made a custom magic circle to help them. At first, it would hurt a lot, but it would go away with time.

While he was overseeing his students, he noticed that some of them already had used the Soul Contract. The average power level in this academy was around the fifth level. The strongest students were around the sixth or seventh level. So, most of those who went to kill a creature to take its soul only managed to kill creatures below the fifth level.

But the level of the creature they killed wasn't actually important. After all, the strength of the ability they gained afterward would be able to grow with them. But it was crucial to choose beasts that could give you some useful abilities.

For example, if one lacks in defense, he should contract the soul of a creature that had a very good one. While thinking that, Arima glanced at Ofia and smiled. The day before, she looked still pale and weak but here she was, practicing stances and sweating as much as everyone else.

When she got the Soul Contract, she unhesitatingly exerted her influence to get herself a live cockatrice. Cockatrices were really rare and although they were really dangerous because of their cursed eyes, if one was prudent enough it was easy to kill one since they were only around the fifth level as well. The reason why Ofia chose this beast particularly, instead of another of higher level was for its strong regeneration ability.

Thanks to that, she healed her weak body that had held her down for her entire life. She was the perfect example of how using the Soul Contract smartly.

The same day, during the last period, when Arima was about to teleport everyone, Isla suddenly called him with an oddly big smile on her face.

He scowled at her. "Do you have a question?"

Isla shook her head. "No, I just wanted to ask teacher a favor."

“What is it?"

"Since you've only been teaching us since the beginning, we've not been able to see teacher in action. Could you show us your own strengthening magic?"

Arima looked around and saw that everyone was staring at him in expectation.

“I guess it won’t hurt,” he shrugged and said. His sigil revolved once and they were instantly put in another dimension. No one actually noticed it except Arister, Lanya, and Night. And perhaps Ofia who had a very good intuition.

"You should take some distance," Arima stated and snapped his fingers. Everyone was teleported away from him. They reappeared far up in the sky and floated there thanks to Arima’s magic.

"Eh? Is that much precaution really necessary?" Isla tilted her head.

"Oh, yeah," Arister snorted.

"Without a doubt," Lanya giggled.

Arima inhaled strongly. He took a combat stance and pulled his fist until his waist.

"[Herculem Corpore] (Hercules Body)," Arima chanted and his body grew a bit taller and burlier.

"[Terminus Confractus, C] (Limit-break, 100)," his muscles contracted and the air-flow wrapped around him each time he made a small movement. There was even some vapor coming out of his body.

He clenched his fist and swung it in a very powerful and fast motion toward the ground. It lasted less than a millisecond. He stopped his fist just before it could touch the ground.

A shock wave struck the ground and instantaneously crushed the ground and created a mile-wide crater. The entire continent started shaking. The crater just continued becoming deeper and larger, as if something was continuously trying to drill a giant hole.

The pressure produced by Arima's fist even reached his students that were in the sky. They were blown away for a few miles but the magic making them float didn't cease. When they stabilized their center of gravity and looked down at the ground, their eyes widened to the maximum and their jaws dropped.

What they saw was Arima standing in the middle of a giant crater covered by shattered rocks and flattened soil. Maybe the ground there would be as strong as concrete if you were to knock on it. You could also see extremely dense dust clouds that had formed around the immense crater if you were to squint your eyes toward the horizon.

"…I-Impossible, how could a human have such a strong body?" Ofia muttered and Lena who was beside her was practically trembling in fright. Even Irian who was a physical strength fanatic couldn't believe his eyes.

Arima exhaled some vapor and looked upward. "Is this enough for you, Isla?"

Isla laughed wryly. "...Yes, it's perfect…" She responded and looked around to only see devastated terrain as far as the eye could see. She gulped and peeked at Arima’s nonchalant smile.