Chapter 15
The Revolutionary Teacher, The First Lesson, and the Shaken Girls
It was a lecture unlike any other—one that drew unprecedented attention.
The venue was the newly established Royal Academy of Magic in the heart of the capital—
an experimental learning institution where the most progressive knowledge in the kingdom was gathered.
From early morning, the lecture hall had been filled with hundreds of students, nobles, soldiers, magicians, even merchants.
All of them had come for one purpose only:
—to witness, with their own eyes, the “public lecture” of the mathematics teacher who had come from another world.
“Alright then, let’s start today by handing out some candy.”
Kai Cross stood on the podium and, in his usual casual manner, pulled out a jar of candy.
He himself hardly noticed how every single movement of his drew the attention of the entire hall.
“You there, kid—you’ve got a scary look on your face, so have one of these. And you, miss—your eyes are sharp, huh? How about a mint flavor?”
“……”
At first, everyone was dumbfounded.
But soon, warm laughter and a relaxed atmosphere spread through the hall.
It was an “introduction with human warmth”—something never before felt in any magic lecture.
“Now then. Today’s topic is ‘the fluctuation of mana.’ But first—what do y’all think mana is?”
“…The power of will?”
“Yeah, that’s part of it. But from where I stand, mana’s more like a bundle of vectors and density.”
Then Kai began to cover the blackboard with visualizations of “mana flow,” using functions and diagrams.
Parabolic trajectories, wave cycles, deformation patterns of magic circles.
What should have been incomprehensibly difficult was, in that instant, organized and made clear through mathematics—
and the air itself seemed to tremble.
(So this… this is what it means to ‘teach’…?)
(This is… Professor Kai’s lecture…!)
With that thought, every student scribbled furiously in their notebooks, eyes shining with excitement.
At the very back of the hall, hidden from notice—
sat a single girl, Filia Estrea, her head bowed as she filled page after page of her notebook with notes.
(I really do love it… the way he teaches.
He treats everyone the same, without distinction…
and even with silly words, he manages to explain difficult things so clearly…)
But she could never say it aloud.
Now, after all this time, she lacked the courage to tell him the reason she had “come back here.”
(To me, the professor isn’t just a ‘teacher’… But if I said that, I feel like everything would fall apart.)
When the lecture ended, the entire hall erupted in applause.
Kai, smiling wryly, set down his chalk and was about to leave—leaving three candies neatly lined up on the lectern—
when someone was waiting for him in the corridor outside.
It was Rutia von Valenstein.
“…Seems it was a success.”
“Never thought that many would show up. I was worried I’d run out of candy.”
“That’s what you were worried about…?”
As she spoke, her gaze dropped slightly.
Deep within her eyes, there was a flicker that was not usually there.
Then, for just a moment, her fingertips lightly brushed and held his arm.
“…Hey.”
“Hm?”
“I’ve been thinking about this a lot. Ever since that ‘contract’ ended…
I don’t know what kind of relationship I should have with you anymore.”
“……”
Kai’s expression grew serious as he looked into her eyes.
Rutia paused only a heartbeat before continuing.
“But I’ve made up my mind. I don’t want to just be your ‘student.’
I want to be… the one standing by your side.”
It was a quiet, but unmistakably genuine confession.
Not spoken as a proud noble daughter—
but as the honest words of a single young woman.
Kai let out a small breath before murmuring:
“…That makes me happy, somehow. Even though I don’t really have anything special to offer.”
“You do. You’ve got something… the power to truly move people’s hearts.”
And then—
The great bells of the capital rang out.
It was the signal of a royal emergency summons.
An abrupt announcement had arrived from the Ministry of Magic:
“A formal request for ‘intervention in the Magic Special Zone’ has been delivered from Elstra.”
“There is also a petition to reopen diplomatic negotiations—directed specifically to Kai Cross.”
“Furthermore, the Head of the Elstra Mage Corps will personally visit the capital under the banner of peace.”
Once again, the story began to move—
toward the stage of international affairs.
