I looked back and forth between the golden pipe and Dersia.

"... What is that expression on your face?"

"I'm not sure how I'm supposed to take this."

"It would be easier to show you directly."

Dersia suddenly began searching for something in a nearby pile of clutter. Yes, a pile of clutter. Looking around, the library's initial clean appearance was gone, replaced by all sorts of research tools and reagents.

It was a public library, but she just used it by herself. Did she say the law couldn't restrain her? It seemed she was right. -Squeak!

Squeak!

"...?"

From amidst the pile, Dersia pulled out a cage containing a white rat. It wasn't dead; it was alive.

A rat?

As I stood there bewildered, Dersia poured water from a kettle into the cage. The rat struggled to survive. But as the cage gradually filled with water, it soon had no room to breathe.

I watched as the struggling rat's movements slowed.

"What do you think?"

"So this is... a warning that you'll do this to me if I don't listen?"

"... Watch until the end."

"Pardon?"

Looking again, the rat, now perfectly fine, was swimming. Unlike before, it didn't seem to be in much pain. Slightly surprised, I blinked and asked.

"Ah, is this liquid perhaps breathable?"

"No. I made it so that it could breathe."

Dersia gestured with her eyes toward the golden pipe I was holding.

"It is a Breathing‑Maintenance Device that I made myself. If you implant it in your body, you will be able to breathe in any environment."

"To be precise, you will be able to live even if you stop breathing."

"Ooh...!"

I covered my mouth and smiled. I had only vaguely thought about somehow using wind magic to breathe. I didn't expect such a clear solution to appear so suddenly.

I smiled brightly and bowed my head repeatedly.

"Thank you. This is far more valuable than gold and jewels!"

"... Hmm, I'm glad you seem to recognize its value. An artifact made by a 9‑Star mage is a treasure in itself."

"It certainly seems so!"

Dersia's expression became slightly smug. I was willing to flatter her a few more times. After receiving such an insane magical tool... ...

Huh?

"Excuse me, Master."

"Hmm. Are we suddenly deciding on titles? I see. I suppose it is necessary. Disciple... is it? Hmmm... that doesn't feel quite right..."

"No. It's not that."

I pointed at the rat in the cage. It was floating. It was dead.

"Why did it suddenly die?"

"... Ah."

Dersia shrugged as if it were nothing.

"Rats can't use mana. They can't last long."

"What do you mean by that?"

"Artifacts naturally consume mana. That's common sense. Once you receive this Breathing‑Maintenance Device implant, you will have to constantly channel mana into it, 24 hours a day."

"That's impossible. I can't just not sleep."

"Even while asleep, you must consciously will it to happen instinctively. There's no other way."

"Any other side effects?"

"From the moment it is implanted, you will no longer be able to breathe normally. In other words, if you don't channel mana, you will die."

"Hmm."

I looked at the pipe with a hesitant expression. So it's not a perfect solution. Seeing me, Dersia gave a meaningful smile.

"Well, you can postpone it for later. If you ask after you've become more accustomed to magic, I will perform the implant then."

"Let's do it now."

I handed the pipe to Dersia. Dersia feigned surprise and asked back.

"Will you be alright?"

"Didn't you already know I would say this? It's better to get these things over with quickly."

"It seems I can't hide anything from you. However, I wasn't just saying you should postpone it."

"As one who has come closest to being a Great Mage, a 9‑Star mage, and as a Master who cares for his disciple, I truly feel I must advise against it."

"And as Dersia?"

"For you, survival itself is an overreach. If you're going to be stubborn, you must be prepared."

This must be what she truly thinks. Master and disciple, I never dreamed of such a sweet relationship. If my struggles could satisfy her interest, it would be a small price to pay.

I placed the pipe in Dersia's hand.

"How is the procedure performed?"

"I have no experience in surgical procedures, so I made it like this. It won't hurt much, so don't worry."

"Pardon?"

The end of the pipe sharpened to a point. There was no time to escape. It spun and floated up, piercing straight through my heart.

"Keuk... huh?"

"It doesn't hurt, does it?"

".. It really doesn't." There was just a slight tingling.

Not even blood flowed out. As I watched in wonder, the pipe slowly pushed its way into my body and began to spread. I couldn't be sure, but it seemed to be attaching itself to my organs.

If I had to say whether I liked it or not, it was definitely not. Apart from the pain, the feeling was extremely unpleasant.

"Thank you for the gift, Master."

But I didn't forget to express my gratitude. Even hypocrisy is a virtue. Whatever she sought to gain from me, as long as it was helpful, I could gladly accept it.

"I heard it earlier, but it doesn't sound bad."

Dersia smiled and brought over some old magic books that were nearby.

"These are the subjects you will learn from now on. In elemental spells, you mainly use wind magic, I see."

"Yes. I thought it was the most immediate way to solve the drowning problem. Though I suppose it's unnecessary now."

"You did well. From learning intermediate magic onward, it is better to focus on honing one thing rather than many."

"Intermediate magic... I've heard of it. It's about combining elemental spells, right?"

"Yes. Elemental spells merely generate simple phenomena. True magic is achieved by combining these phenomena to advance into incomprehensible realms."

"Hmm, just hearing that doesn't make it easy to understand."

"It's the difference between creating a fireball and creating a living fireball. Ah, and from this point on, while you are being taught by me, the use of heart‑realm magic is completely forbidden."

"... Wait, hold on. Why?"

I had been thinking I would follow almost any process, but I couldn't help but protest. I just figured out a way to deal with the water pressure, even a little.

"Wouldn't combining my magic with those elemental spells produce better results?"

"Yes. That could be."

"Then why..."

Instead of answering, Dersia walked up and shoved my chest hard. Naturally, I fell backward. Much more slowly.

I wasn't hurt. When the back of my head touched the floor, it made only a tiny tap sound. I knew the pressure had gotten worse, but to this extent...

I sighed and got up.

"I didn't realize it was this bad. Did you expect this?"

"I saw in your walk that you were pushing through something."

"... Hmm, it's convenient, so I ended up using it often. At some point, the resistance to it disappeared as well."

"I'm not trying to blame you. Telling you not to use that power is like telling a bird not to use its wings. It's foolish. However, we must set a limit."

"A limit?"

"Yes. If you come to understand your magic more than you do now, an even greater pressure will come. You should wait until you have completed enough training to withstand that pressure before you try to learn more."

"Thank you. Currents, Tide Sense, water pressure... I'll have to seal them all."

"...?"

Dersia tilted her head and asked back.

"I understand the first and third, but what is the second one?"

"It'll be faster to show you. Could you hold out your fingers behind your back? You changed it to three. Now four... no, stop changing it. Nine."

Dersia narrowed her eyes and looked at me with an expression of disbelief.

"Your progress... is too fast."

"It's not strange for a bird to fly, is it?"

"It is strange for one to fly when its feathers are not yet dry. This was not something to be taken lightly. Do not ever use it without my permission."

"I'll keep that in mind. I'll seal it and focus on honing my magic."

"When did I say I would teach you magic?"

"?"

"Open it."

The book I had assumed was a magic book contained something familiar.

Body‑reinforcement techniques.

"Haha."

"It can't be helped. Jern, right now you must focus on the pressure. Even if you can't withstand the pressure, you must build a body like steel that won't be swept away by it..."

"No, I think it's fine to skip the first step."

This time, it was Dersia who tilted her head. I handed her the copy of the knight’s Body‑Reinforcement manual I had been carrying.

".. Where did you get this?"

"I have my ways."

"Haha."

We looked at each other and laughed.

"Breathing, and body‑reinforcement techniques. You reached the same conclusions as me."

"Well, my methods were nothing compared to yours."

"That is merely a difference in the means available. Let's see, it will take about a month."

"... What will?"

Before she could finish her sentence, the pipe entered my body completely. At the same time, I started to suffocate.

"Heub..."

Seeing this, Dersia calmly advised me.

"Circulate your mana. Even the feeling of pouring it directly into your respiratory system is fine. That's how you can breathe."

Still, I couldn't breathe. However, strangely, the feeling of suffocation disappeared. I looked down at my limbs in admiration.

"... Puha. This is strange. Will I be able to do this while sleeping?"

"You must. Also, that alone is not enough. You must be able to do it unconsciously during intense combat, or even when you're unconscious. Otherwise, even the smallest mistake will kill you."

"You have a training method, right?"

"Yes. Learning with your body is the fastest way."

Dersia showed me a poster that was tucked between the pages of a book. On it were the words, [End‑of‑Term Combat Exam / Children’s Class]. Naturally, a question arose.

"Um... what is this?"

"It's the first combat tournament that noble children attempt. You will challenge it."

"?"

"It must become second nature to you. The process of channeling mana must be an act that precedes thought. Go and get beaten up as much as you can. If you faint, ask them to splash water on you."

In a situation where I'll pass out if I don't consciously channel mana? After long deliberation, I made my decision.

"Please take the pipe out."

"No." It seemed it was not an option.

Dersia had taken a disciple. It did not take long for that rumor to spread.

"... What? No, didn't that elf reject even the princess?"

"She did. Just what brilliant talent did she see to choose them? From which family is the child?"

The mage who held nine stars in her eyes. Such beings do not easily take disciples. That's why, although they were surprised when she rejected the princess, everyone understood.

They judged that a mage of her caliber would surely not be moved by anything less than a talent that could astound her.

"A... a commoner natural body, they say...?"

"???"

And so, this part became a problem.

"And the private tutor of that underachieving student Aletus found at the orphanage..."

"No, what in the world..."

The rumor, which went far beyond common sense, repeatedly set the nobles' tea parties ablaze. But the conclusion always converged on one point. It had to be.

"... Just how outstanding are they?"

The disciple chosen by the one who rejected the princess. Was an orphan, a commoner. A half‑breed not even worth acknowledging.

No matter if they had the achievement of saving other children, no one in their right mind would choose them. And there was no way Dersia would have given bonus points for the goodwill of saving others. Just how outstanding, how brilliant was this talent.

For her to take someone of such low birth as a disciple. The rumors grew like a mountain. ...

Gulp. And.

Elysia, who was closest to that question, swallowed dryly in front of the library.

She knew.

Unlike the world's assessment, Jern was not particularly more outstanding than others. That he was an ordinary child, not so different from herself... That's why she thought the many suspicions that had arisen in just two weeks might be tormenting Jern. '...

I have to comfort him.' Elysia clutched the letter in her hand. She had been summoned for her first lesson. ...

To this library. Her hands trembled. Goosebumps rose at the thought of having to face Dersia's piercing eyes once again.

Still, for Jern who had saved her, she opened the door.

Clank!

"E-Excuse me-gyaaaaaaaaaaaaah!!!"

Elysia, having opened the door, let out a scream.

"This is doable. Let's go again."

Jern, his legs tied, submerged headfirst in a water-filled cylinder.

"... Jern, you are truly insane."

And Dersia, sighing as she plunged his head back into the water.