Matter was concentrated energy, and thus the world was energy. Everything was made of it. Thermal energy, potential energy, kinetic energy, electrical energy, chemical energy, nuclear energy, there were different types of energy.

And then there was mana.

It had some special rules, but part of it still followed the laws of physics. That meant it could be converted into other forms of energy. In fact, preventing mana from dissipating into heat was usually one of the first things a mana user had to learn to do when trying to cast spells.

The issue with mana was that it only occurred in places where living beings existed, and even then in very small amounts. Some races called it life energy or vital energy, though mana was the most widespread and commonly agreed name in the tower.

Mana's connection to living beings was even more obvious in the simple fact that mana could be controlled with a thought.

Earth had small amounts of mana, but still enough to be found and used. Akira Sakura had sent a mana wave at Luke. It had been harmless, but had proven that it could be done.

Unfortunately, humans weren't born with mana channels, so at most they could slightly heat an area or slightly increase one's natural regeneration using it.

Mana channels, also called spiritual roots, mana veins, or even magic spirit, were highly versatile things that originally existed only in the souls of some beings, which were aptly called magic beasts.

To begin with, mana channels let mana users accumulate and store mana inside them. They also passively absorbed mana from the environment and made it easier for mana users to actively do so. The great majority also purified mana to some degree, which made it more powerful. Finally, mana channels acted as a sort of veins that let the mana user easily and quickly push mana from their entire bodies.

If a mana-less race entered the tower, it gave them mana channels once they passed the Test Floor. As good as that might be, that didn't make the race magical, so offspring born in the tower would not come with mana channels either. They would have to be given their channels by someone else or build their own, as the Test Floor could only be used the first time a race entered the tower.

That was good news for him; it meant he had memories of how to build mana channels without the tower's help.

Building mana channels was both easy and hard at the same time. Easy because it didn't require a lot of skill, and the little knowledge it required could be easily found in the tower. Hard because it was incredibly painful.

It started with building a single channel from his chest into his heart, but with a caveat: the channel would exist in his soul rather than his body. His memories didn't tell him what souls really were. What it did tell him was that they existed as ethereal, featureless forms superimposed on people's bodies. And in the tower, when someone died, their souls were taken to the Hell Floor.

He shivered just remembering the name of that place.

That first mana channel would be a mere first step so he could move to the second and much more important one, creating his mana core. That's what made mana channels actual mana channels rather than just holes in the soul.

But that would come later. For now, he had to focus on his first mana channel, and that started with the simple task of feeling mana.

Mana was everywhere around humans, just like air, but it didn't move naturally. Could a person feel air if it didn't move? It wouldn't be different from what they always felt, so how could they differentiate it for the lack of air?

One way to do it would be by putting someone in a place devoid of air, then taking them back into a place with air. The different sensations might help with that. Likewise, the easiest way of feeling mana was by temporarily putting the trainee into a mana-deprived zone, but Luke didn't have access to any such places.

Luckily, he had had the second easiest way, which had even already been used on him: feeling mana moving on his soul's "skin."

Just like humans could feel air by merely putting a hand in front of their breathing nose, so had he identified Akira's mana wave going by him. It had felt icy cold, meaning it was the most impure mana possible. The purer the mana, the warmer it felt—which made it harder to prevent from turning into heat, by the way.

Luke focused on remembering that cold feeling and on feeling it surrounding him. That was the first step. Only once he felt mana could he assert his will over it and start building his channels.

For one hour, he tried.

For one hour, he failed.

Then he decided it was time to ask for help.

Luke had to admit he felt some trepidation about asking for it, but his granddad's words were still fresh on his mind. He was a warrior and he would fight against whatever the world threw at him. If an obstacle was on the way, he would surpass it. He might have tried harder to surpass it alone if he had had the time, but his granddad's life was on the line, so he would look for help this time.

It might be a bit silly of him to think that, but he believed that warriors shouldn't be above asking for help when they needed it.

Luke left the room decidedly, and found the old maid from before sitting on her knees on the outside. She stood up and bowed slightly as soon as he appeared. "Do you need anything, honored guest?"

"Are you going to sleep here?" he asked, his surprise even taking his task out of his mind.

She smiled. "No, honored guest. I'll leave at midnight."

That made more sense, but still... "Don't your knees hurt?"

She seemed confused by the question for a moment, then her eyes widened a little in understanding. "I've been sitting seiza all my life." Thanks to his Universal Linguist skill, Luke knew that's how they called sitting on their knees. "Like most Japanese from traditional families and martial artists, I got used to it. That's the proper way to sit on tatami."

Luke nodded. Unlike the inside of the rooms, tatami mat flooring also covered the corridors of the second floor.

He took a deep breath. "Can you bring me to Akira Sakura?"

She bowed slightly. "Of course. Please, come this way."

To his surprise, he wasn't led to her room, but to the dojo instead. Inside, they found Sakura and Mr. Akira wearing martial arts kimonos and fighting each other.

Luke analyzed the old man's movements with his memories and instincts, and what he found left him astonished. Mr. Akira was a true master of martial arts, and highly experienced too. His movements were fluid like water and precise like a laser. His defense felt like a steel wall and his attack like a torpedo. He was strong and agile, and Luke was sure he couldn't win against the man before his strength and agility reached at least the average for adults.

Sakura was like a kitten fighting a tiger. Not only were her stats inferior to begin with, she was clearly afraid for some reason, and angry too. The emotions clouded her judgment and made her fight even worse than she had against Luke, when she had held her punches back.

While Luke watched, Mr. Akira dodged one of her punches and easily grabbed her arm then twisted it on her back. To finish it, he grabbed her neck with his other arm. She had been dominated.

Coincidence or not, the finishing position ended up with both looking at the door, where Luke stood with...

...no one. He looked to the side, and found himself alone. The maid had disappeared without making a sound.

'Wow! What the hell? A ninja?' he thought.

The fear in Sakura's eyes disappeared when she saw Luke, replaced instead with anger. She really disliked him, didn't she? Typical bully, hating someone for no reason at all. Mr. Akira's eyes showed only a slightly surprise, and even that for such a brief moment that Luke might've imagined it.

"Mr. Kells," Mr. Akira said while releasing his niece. "I was told you're a great fighter. Would you care to entertain his old man?"

Luke shook his head. "I'm sorry, but I'm kind in a hurry. Can I talk to her?"

"Certainly," the old man replied. "We are done here, niece. Think about my words and your mistakes."

Sakura bowed low to him with her hands clasped together and extended in front of her. He nodded back and left the place. Only after he closed the sliding door behind him did she turn to Luke. "What do you want?"

"You said you owe me one," he started, boldly staring at her eyes. This was for his granddad. He wasn't allowed to fail here.

"Oh, you're looking me in the eyes? Aren't you afraid I'll punch you?" She asked haughtily, but he just ignored her. She tsked. "Have you decided what you want, then?"

"Yes. The mana wave you used in the class. I want you to do it again until I can feel the mana around me."

She frowned. "Mana wave? Do you mean the ki burst?"

From the little Luke knew, ki, qi, or chi was the name given by some Asian cultures to vital energy. It made sense that they would call mana by a local name.

"Yes."

"Do you have any idea how long it can take for you to feel ki by yourself?"

"With your help? Weeks at worst. I'm confident in doing it today."

Sakura looked at him suspiciously. "You have a big secret, don't you?" He shrugged. "Creating ki bursts is tiring. I can do that less than a hundred times per day."

"That'll be enough."

She nodded, and then, without warning, just clapped her hands. The cold mana wave went through him unimpeded. "I can do one every few seconds or so," she said and clapped again.

Luke didn't waste any time. He sat down with legs crossed, closed his eyes, and concentrated.

Today, he would definitely feel the mana around him.

"One... hundred," Sakura said, looking dazed.

Controlling mana was easy, but it still required some willpower, and the more you used it, the more tired you became. It wasn't much different from studying advanced mathematics for hours and hours, only your mind got tired much quicker.

Mana that hadn't gone through a mana core was weak and more resistant to control. The mana waves she was sending Luke's way required so little mana that even an untrained person who had just learned how to use mana should be able to do it ten or so times. For Sakura to do it a hundred times spoke of at least months of training her willpower, if not years, depending on her talent.

"I'm done," she informed and just left. She was so mentally drained that she almost tripped twice. For a trained fighter like her, that was very telling of how demanding controlling mana could be.

Luke didn't reply. He was still focusing on the environment around him.

And the moment she closed the door, he felt it.

Mana.

Impure mana was cold, and he felt that he was surrounded by it. It was hard to pinpoint that sensation because one felt mana not with the physical body, but the soul. Unlike the body, the soul had no innate temperature, so it became as cold as whatever it touched, in this case, mana. That made feeling mana harder and was also part of the reason being in a mana-free zone made feeling mana much easier.

He had required help, but suddenly, he managed to differentiate between his own soul and the mana around.

He had done it.

Once he did it the first time, it became easy to feel the mana in less than a minute. The soul could only feel things touching it, just like the body's tact worked, so he could only feel the mana touching him. There was a way to "cheat" it a little, but that would depend on his mana core.

And to build a core, he had to make the mana obey him.

Focusing on the surrounding mana, he willed it to obey him. Mana was energy, yet now it felt to him like cold steam moving through his soul's "skin." He focused on a few wisps of it and mentally ordered it to move.

It wasn't hard, only tiring. Mana was very reactive to anyone's will. You just had to make sure you were feeling it and that it was within your area of influence—touching your soul.

When he willed it, the mana obeyed at once.

The wisps of cold steam moved over his soul's like tiny snakes, and Luke shivered. It felt like a sort of weight had been added to his thoughts as it moved around. It was hard to explain, but he was literally moving stuff—mana—with the power of his mind.

He had done it, he had felt and taken control of mana.

Now, to create his first mana channel.