[Explosive Advantage] Engaging in a Mental Battle with the Strongest Evil Spirit Since Birth, I Exceeded the Measurable Magic Limit – The Humble Conquest of the Cursed Child - Chapter 21

(“Hey, Douma… I’ve got a bit of a favor to ask. Could I borrow some of your mana…? I won’t be able to pay you back though.”)

{Sure, go ahead.}

(“…Eh? R-Really? You’re okay with it!?”)

{Yes, I don’t mind.}

(“I-I mean, not to be rude or anything, but… why are you okay with it?”)

{What’s this? Don’t want it after all?}

(“Ah, no, sorry! That’s not what I meant—”)

{…Why I gave you permission? That’s easy.}

(“…”)

{Because you asked sincerely.}

(“…!”)

{You didn’t pretend it wasn’t a favor, and you didn’t try to hide that you couldn’t repay me.
That’s only natural, don’t you think?}

(…This Douma-san… sometimes he says such perfectly reasonable things, it actually throws me off…)

“K-Kai-kun… so, what’ll it be?”

Kurita, the soft-spoken instructor, cautiously asked Kai again.

“Y-Yes… I’ll do it!”

“O-Oh, I-I see…”

(“Douma… I’m authorizing limited use of your mana. Go ahead and do your thing.”)

{Understood.}

(…Alright, then… I’ll just partially open the ‘faucet’…)

Inside his mind, Kai carefully imagined turning a valve—the faucet that would let Douma’s mana flow into him.
Just enough to stay in control—no more than that.

(…)

As he did this, a thought quietly formed in Kai’s mind.

(“…Sorry, Douma.”)

{Hmm? What for?}

(“…It’s just… I still can’t bring myself to fully trust you yet.”)

Even so, Kai felt almost ready to throw that faucet wide open. That’s how far he’d come.

{That’s fine.
Cautious types don’t bother me. I wasn’t one myself, after all.}

(…!)

{Anyway—it’s time, isn’t it?}

(“Yeah… it is.”)

{The technique is… Flame Technique: Firefly Flame.}

(“Got it.”)

Kai extended his arm and held out his palm, facing upward.

Then, he relinquished control—allowing Douma to use the mana.

“Flame Technique: Firefly Flame”
【Flame Technique: Firefly Flame】

“—!”

“——”

“……!”

“………”

All four onlookers were struck speechless.
Kurita, Hyoudou, Ame—and even Kai himself.

“…S-So beautiful…”

Kurita whispered, a single tear rolling down his cheek.
It wasn’t theatrical—he was genuinely moved to tears.

Douma’s Firefly Flame was a flame of darkness.

A perfectly spherical orb of black fire floated in stillness, unshaken by wind, as though time itself had paused around it.
It burned quietly, with solemn dignity.

(…)

Kai, too, found himself mesmerized by the flame’s dark brilliance.

In that moment, a vision flowed into his mind through the mana—a stream of Douma’s thoughts and memories.

It was as though he were watching Douma’s life unfold from Douma’s own perspective.
Scene after scene of him practicing relentlessly, tirelessly honing his technique.

(How much…
How much training and discipline did he put into this…?)

Endless, painstaking effort.
An unwavering respect for the art. A deep, almost obsessive commitment to mastery.

It was so sincere—so honest—that it was almost impossible to reconcile with the brash, sarcastic Douma Kai knew.

(“Douma…
You really are… incredible.”)

“Huh!? Where did that come from all of a sudden!?”

(“No, I just… really thought you were amazing. Sorry—I’ve got no words for it.”)

{……If you ask me, that Tasuke guy is more—ah, no, forget I said anything!}

(…? Tasuke…? Oh—right. Because ‘Kai’ can be read as ‘Tasuke’ in kanji…)

Kai paused, a little surprised.

(So he does know how my name is written…)

And with Douma’s help, Kai had somehow (questionably) made it through his mana control training.

Just then, someone lightly tapped him on the shoulder.

(Hm…?)

Turning around, he saw Ame standing there.

“What’s up, Ame-san?”

“Um, Kai-kun… this might be asking a lot, but… would you train with me?”

(Huh…? Did she mean ‘let’s train together’ and just worded it weirdly…? Still, I couldn’t ask for more. I’m fired up to train anyway!)

“I’d love to. Let’s do it.”

“Thank goodness… Then, Kai-kun, let’s meet in the Chamber of Stillness during free time—”

“H-Hey! You two can’t just decide that on your own…!”

Hyoudou, who had been listening in, tried to stop them.

{HUH!?}

In a complete 180 from the serene Firefly Flame, Douma suddenly radiated a dark, threatening aura.

“Eek…! G-Go right ahead…”

(Crap—left the mana faucet open…)

“U-Um, even so, Kai-kun…? You’ll still need to do this under supervision…”

Kurita looked extremely reluctant, but as an instructor at the Seigoin facility, he couldn’t ignore it either.

(Well… it is his job. Can’t blame him.)

“Th-Then, Kurita-sensei—would it be alright if we asked for your help? I know it’s during your personal free time, and I really appreciate it…”

“……S-Sensei!? Y-Yes! If you’ll have me, I’d be honored…!”

And so, Kai ended up training together with Ame and Kurita.