The Flame of Tranquility
"Hachoo!"
With a high-pitched sneeze more befitting a rodent than a person, Shirogane Rui sniffled and turned a resentful glare on me.
I had driven her heat up until she was right on the brink of death in a dungeon that grew colder the hotter she burned, then left her like that for a full hour. That look was only natural.
Even if an Awakened stood beyond ordinary human limits and could reinforce their body with mana, there were still hard boundaries. Still, I had used Kallion as a living shield so the knife-edged north wind never touched her, and I had lit a fire for her. I had taken every follow-up measure I needed to. There was nothing for me to feel guilty about.
She knew it too, which was why she settled for glaring instead of complaining out loud. Thanks to that stretch of forced rest, the basic framework was finished. With one stage complete and my concentration broken, I finally let myself breathe.
"...Is it done?"
"For now."
Her reply came out flat and lifeless, the way only someone who had been half-dead could manage. I answered calmly. When I refused to play along with the open sulking, she pouted, turned her head away—and still kept sneaking glances at me like a sulky child. Ignoring the performance, I ordered Kallion to apply the half-finished formula.
Whoosh!
Flames rose and wavered above the magic circle drawn in empty air. Slowly they shifted, taking the shape of a sword. It was only a temporary form, fire given the structure of Magic Armor so it would hold.
In actual combat there would be no need for a separate casting of Magic Armor; Shirogane Rui herself would serve that role.
"...It's pretty."
Staring at the blade of flame, she forgot her sulking entirely. Her eyes sparkled.
Attention successfully diverted. Next came the demonstration.
Long-winded explanations would be wasted on someone who learned by feel. Better to show her with her own eyes and let her body copy it.
I concentrated the fire into the sword. Like a blacksmith working metal, I poured flame in, then drew it out again. With every cycle the Magic Armor flushed red, then white, then red once more.
Then, at a certain point, even after the fire was withdrawn the blade stayed crimson.
"...!"
She must have recognized the phenomenon instinctively—the same heat that built up inside her own body. Her expression sharpened; she began studying the process with real seriousness.
While the fire energy was still accumulated, I released the heat from the Magic Armor in a single burst. The release point was the very tip of the blade.
Hisssss!!!
The sound was exactly like the lid of a pressure cooker flying open. The liberated heat exploded outward in a scorching gale, every scrap of condensed power freed at once.
Add actual flame and mana to that and you would get a full detonation. But this demonstration was meant to show the aftermath of the release, not the explosion itself, so I deliberately left that step out.
"What I just showed you is the method you normally use, senior."
When I brought the Magic Armor closer, the tip of the blade was badly damaged, spiderwebbed with cracks. It was no longer usable.
"Huh? Wha..."
Her face went blank as she processed the entire sequence.
I had not needed to explain the risks; she already knew them. It was her own technique, after all.
So why the shock? Because the destructive power was greater than she expected? No.
She was stunned because I had dissected and reproduced a technique she had spent years developing—in a little over two hours.
Without Kallion's absurd power I could never have done it either, so I would have preferred she stop looking at me like I was some kind of monster.
"As you can see, condensing the heat into a single point and releasing it produces tremendous destructive force. The inevitable price is severe cumulative damage to the body."
Kallion, reading my intent, poured mana into the ruined Magic Armor and restored it in moments. Unlike the earlier demonstration, the heat gathered again almost instantly—then the playback froze.
"From there, I came up with only one improvement."
Instead of trying to dump the heat all at once, regulate it so that a constant, manageable level is always maintained from the start.
"I already try not to let the heat build up... but it's not as easy as it sounds."
Shirogane Rui immediately voiced her doubts. This was her power. In three years she must have tried every possible method of controlling her body's heat.
As if to prove me right, she began listing her past efforts.
She had equipped artifacts that radiated cold. She had swallowed elixirs steeped in chill. All of them had been temporary stopgaps. Her constitution—the blood of the Descendant of Flame who commanded fire-demons—was simply too high-grade for such half-measures.
No matter how high she raised her fire resistance, no matter how much she reinforced her body, the result never changed.
The more she used fire, the foggier her head became. Her vision narrowed, sometimes even wavered. Thought slowed. Her brain felt like it was boiling; her mouth turned desert-dry. It was like being thrown naked into a sun-scorched desert.
The irony was that if she really were thrown into a desert she would barely feel the heat—only the grit of sand in her mouth.
Even volcanic lava that could melt a human body on contact felt lukewarm to her.
No inferno in this world could wound her. The only fire that could was her own. And so the heat that fire produced was the only thing that could choke her.
The stronger her command of flame became, the faster the heat rose. That fact left her frustrated.
She could burn fiercer, wilder—she was sure of it. Her own body simply refused to allow it. So she was forever stuck in incomplete combustion.
The fuel that had always fed her fire turned into black soot clogging her throat. It was suffocating. She had tried every way she could think of to break free, and every attempt had ended the same: failure, failure, failure.
Even the method of detonating the heat in one violent burst had been something she stumbled onto by accident while thrashing her body like a self-destructive weapon.
"And you're saying you can fix that...?"
A smile touched her lips without her noticing. Not mockery—just a hollow, resigned laugh. Helplessness was already swallowing her.
"I can."
"Ugh...!"
The flat, absolute certainty in my voice made her grind her teeth. It felt as though every desperate effort she had ever made was being dismissed. And yet, stronger than the resentment was hope. How many times had she hoped before? How many times had she tasted failure and bitter disappointment?
She knew this might be just another empty expectation. Still... when someone spoke with that much confidence, maybe it was worth believing one more time.
"...Haa."
She slowly unclenched her jaw. Her lips trembled, but she forced herself to ignore it.
"...Really?"
Snap!
I gave no verbal answer. The snap of my fingers was enough; the flaming weapon floating in the air began to glow once more.
Seeing is believing. No need to talk myself hoarse—I would simply show her again, the same way as before.
"Picture an air conditioner and a refrigerator. You don't need to know the exact internal mechanisms. What matters is the phenomenon itself: using a refrigerant as a medium to maintain a set temperature."
With mana, a solid image is already more than half the battle. Even a rough mental picture is enough to make mana move.
It is like drawing. A person who has never been taught can still produce a picture simply by moving arm and wrist over and over. Add proper study and the result becomes finer, more complete. In short, the perfection of the image directly determines the perfection of the mana technique.
That was why I deliberately named the two most familiar sources of cold in everyday life.
The explanation was so far removed from anything she had learned that her face went blank; she was clearly still lost.
"The concept itself is simple. Think of a room as your body, senior."
"My body... as a room?"
"Yes. Using this sword as an example, the sword itself is the room—the vessel holding the energy."
Once I framed it in more fantasy-friendly terms, she finally nodded in understanding. I held up the Magic Armor, still glowing cherry-red even without active flame, and continued.
"Imagine a room stuffed full of heat on a sweltering summer day. To cool it, you need to turn on the air conditioner. What do you need first to make it work?"
"Uh... you have to switch the power on, right?"
"And then you set the temperature with the remote."
Through the Link, Kallion read my thoughts in real time and created a flame beside the Magic Armor.
"This fire holds heat equal to the accumulated heat inside. Remember that."
"...Yeah. I've got it locked in."
Even half-dead she was still unmatched when it came to fire. She was also the one who suffered because of it. The sheer effort she had poured into solving that suffering showed in how instantly she grasped the nature of the flame just by looking at it. Only someone with profound understanding could have read that much so quickly.
I closed my mouth for a moment and steadied my breathing.
Was teaching this woman this power truly the right choice? The doubt lasted only a second. The water was already spilled. It was far too late to turn back.
"Now we come to the air conditioner I mentioned at the start. An air conditioner usually comes as a set—indoor unit and outdoor unit. Why is that?"
"Um... to push the hot air outside and bring cool air inside?"
Half right. Her mental image included expelling hot air, but not the process of creating cold air in the first place.
She simply did not know the principle of cooling by vaporization heat.
"Have you ever seen people spraying water on the street on a hot day?"
"Yeah, I have."
"That's the same principle as an air conditioner. When the water evaporates into vapor, it sucks up all the surrounding heat."
"...So because the heat is used up in the vaporization, the area around the water cools down?"
Correct.
Once I broke it down this simply, she was starting to catch on.
Right now she looked a little dull, overwhelmed by her own power, but the mere fact that she attended this academy proved she was far above ordinary people. Once she got the hang of something, she could follow quickly.
"But this is..."
"Yes—it's basically the same one-dimensional heat removal you've been using until now. So we have to take the idea further."
Whoosh!
Flames flared.
"And every single step has to be accomplished with fire alone."
Gulp.
Shirogane Rui swallowed hard and gave a slow nod.
"First stage: compression. The process itself is almost identical to what you've already been doing. The difference is that you must never release it—you keep the compression going."
The fire outside the sword slowly compressed, the scarlet flame kneaded into a near-spherical shape. Smaller now, yet far brighter, it radiated an even more intense presence.
"You remember that the fire outside and the heat inside are equal, right?"
"Yeah."
"From this moment, this fire will play the role of the hot exterior."
"...??"
She clearly did not follow. How could fire act as the hot outside? That was the limit of one-dimensional thinking.
Even I, who came from a completely different world of concepts, had adapted to mana—the pure crystallization of the unscientific. For people born in this world to fail at the same adaptation was almost pathetic.
"...In the first place, this fire is not burning physical matter. It burns mana as fuel, producing heat and light. That is the phenomenon we are recreating."
People often assume that as long as you have fire magic you can create endless flame.
Wrong. Even a successful spell will gutter out if there is not enough mana to burn.
In other words, the magic itself does not create the fire.
Most fire-magic formulas focus on ignition. The spell's first purpose is not to burn mana but to produce a spark.
That spark immediately begins consuming mana and grows into a proper flame. Controlling that flame is the origin and foundation of fire magic.
Therefore, no matter how much fuel (mana) you have, without a spark (the formula) no fire will rise.
That is why people without affinity can thrash all they like and still never cast magic: affinity for fire magic is precisely the power to create that spark.
Fire magic, then, is simply a spark enlarged by the continuous supply of mana.
As long as the supply continues, it keeps burning, giving off light and heat. Cut the supply and it shrinks back to an ember and dies.
Structurally, fire magic always wants to return to its original spark. In a sense, that is close to the concept of liquefaction heat.
The opposite of vaporization heat: when a gas returns to liquid it releases energy—liquefaction heat.
Just as vaporization heat steals surrounding heat, liquefaction heat dumps heat into the surroundings.
Magic works the same way. While fire magic is active, heat remains. When the magic vanishes, the residual heat dissipates quickly.
So what choice do you make if you want to remove the leftover heat from a place that fire has just swept through?
Simple.
Either interfere with the magic itself, collapse the foundational formula so the heat never existed in the first place... or clash it with an opposing-attribute magic and cancel it out.
What she needed was the latter. To cool the heat, she had to splash water on it.
In other words, she had to generate a mana-based vaporization heat. To do that, she needed to deliberately extinguish a "fire" equal in intensity to the heat her body carried.
Simply cutting the mana supply would just be a dispel. The residual heat would remain, rendering both vaporization and liquefaction meaningless.
Cooling by vaporization heat requires constant temperature and pressure.
The spherical flame floating beside the sword already satisfied both. All that remained was to prepare the "water" that would extinguish that flame, collide the two, and snatch away the thermal energy for rapid cooling.
"The reverse of fire is water. From among the runes that carry the meaning of tranquility and do not clash too badly with fire, we select and combine them with the flame."
And the result was this.
A concept that should have been scientifically impossible, yet forced into existence through mana—a mad fusion of mysteries.
Whoosh...
That crystallization bloomed above my palm.
A mysterious flame that glowed a pale sky-blue, almost the color of water. Shirogane Rui's gaze locked onto it.
In her eyes burned the absolute resolve not to miss even a single instant of what came next.
It was not blue because it burned at extreme temperature. It was blue because it carried the power of water.
Even that color originated from my own mental image; if the concept alone had been expressed, the flame would have been as colorless and transparent as water itself.
"If we have to name it, let's call it the Flame of Tranquility."
Exactly what it was: fire that held the calming power of water.
It burned softer and more translucent than ordinary flame. The way the flames swayed like gentle waves seemed to soothe both body and mind just by being watched.
Apparently grafting the effect of "tranquility" onto fire produced that side benefit.
I flicked the flame toward the compressed sphere of fire.
Ssssshhhhh...!
A sound that should never have come from two fires colliding rang out—a dull, heavy noise like water dashed into searing oil and the lid slammed shut.
There was no spectacular spraying of sparks. The two differently colored flames simply intertwined, calmly shrinking together.
As the Magic Armor's fire died, the heat inside cooled just as rapidly. All that remained was to repeat the process until every last scrap of internal heat had been stolen away.
When I brushed aside the pale-blue flame, the Magic Armor sat there restored to its original pure white, without a single scar.
"...Ah."
Shirogane Rui let out a short, breathless sound. Then she lowered her head and trembled.
Whoosh.
At the same moment, flames erupted from her own body.
She struggled desperately to imitate the Flame of Tranquility Kallion had created, but the more she tried the larger her ordinary flames grew. They refused to obey her will.
That was only natural. Kallion could produce it effortlessly; for her to maintain the same form would require far more effort than she had yet given.
"Ugh... kuh..."
She did not give up. Even when the heat overwhelmed her and she staggered, even when she collapsed, she never stopped using her fire.
Of course she didn't. After wandering so long in darkness with no answer in sight, a clear path had finally appeared before her. She could not simply stand there staring.
She would run herself ragged to reach that path as soon as possible.
With this, most of the problem is solved.
Through this opportunity, Shirogane Rui's growth was all but guaranteed. The faculty who knew her better than anyone would notice immediately.
Moreover, the Flame of Tranquility and the heat-elimination technique built around it could be applied to anything involving heat, not just her. It possessed genuine practical value.
Therefore Development and Creativity were as good as passed.
What remained was Cooperation... and that would depend on how far she could grow in the four days left.
I looked down at Shirogane Rui, who had finally sprawled flat on the ground, half-delirious from the heat, and spoke.
"Senior, this is your homework. Master it on your own in the time remaining."
If she wanted another demonstration I would show her anytime. But further explanation was finished. I had already invested this much for her sake; she was not to bother me any more.
"Mmm..."
Even in her exhausted state she nodded slowly, eyes glistening. Satisfied, I sat back down.
There was still plenty of time left before the dungeon clear.
Slurp.
I accepted the CalorieMate Hive handed me from the shadows, drank it, and let my eyes rest once more on the endless white landscape.