A person who was always working hard.
That was the impression Filiestra Adinson had of Brendan Walker.
Even though he had said he wasn't used to such things, he pulled everyone together as the class representative, handled requests from Professor Blanchard, and holed up in his research lab the moment classes ended.
He was still in the lab when Filiestra headed home, and he was already there when she arrived in the morning. She worried about when he ever slept, yet she had never once seen him dozing off in class.
They weren't particularly close, but they weren't on bad terms either.
They only spoke occasionally when comparing notes or verifying coursework.
Outside of school, they didn't talk at all.
That was the full extent of her relationship with Brendan.
Yet yesterday, completely out of the blue, he had proposed a joint research project.
His reasoning had made sense, and since Filiestra was intrigued herself, she had accepted.
He was apparently going to forge a magic sword tailored specifically for her by the end of classes today. In fact, he was forging that sword at this very moment, which was why there was no sign of him in the classroom. According to Professor Blanchard, his absence was officially marked as sick leave.
"I wonder if Bren-kun isn't feeling well."
Between classes, her friend Amae muttered absently.
The one who immediately shot that down was Garry Locke.
"Nah, that guy was in his lab today."
"Hmm. Guess he might be sleeping, then."
Watching Amae give a blunt reply through a yawn, an idea popped into Filiestra's head.
If she didn't know much about Brendan Walker, she could just ask someone close to him. It was simple enough.
"Hey, Amae-chan."
"What?"
"What kind of person is Walker-kun?"
"Huh? Why do you ask?"
"Well, you talk to Walker-kun a lot, Amae-chan, so I thought you might know him well."
"..................Huh? Is that where this is going?"
"Eh?"
That had clearly come out wrong.
Filiestra hurriedly shook her head and clarified what she actually meant.
"Ah, no, um, I'm going to be helping Walker-kun with his research soon... And since I haven't talked to him much before..."
"Hmm."
"You seem to get along well with him, Amae-chan."
"You think so?"
"Yeah."
For some reason, at that exact moment, the perpetual drowsiness vanished from Amae's eyes.
"...Well, Bren-kun can be weirdly clueless, so I just teach him various things."
Just when Filiestra thought Amae had lapsed back into silence, she paused for a beat and slowly spoke.
"You know Bren-kun?"
"Yeah."
"When he thinks about dirty things, he gets a nosebleed, so watch out."
A question mark practically materialized above Filiestra's head.
She couldn't comprehend what she had just heard.
"So yeah, when he's got a nosebleed, it's a sign he's thinking naughty thoughts, so watch out. He did it around me once."
"Huh? What?"
"As for his personality... yeah, that's about it, I guess."
"Whaaat...?"
"Also, Bren-kun will eat the vegetables you don't like."
What in the world was she supposed to do with that?
None of it made a lick of sense.
"Lady Amae~! Lady Filie~! Our next lecture is outdoors, you know~!"
"Guess we should go too."
Prompted by Luluck's calling voice, Amae pushed herself up from her seat.
Meanwhile, Filiestra remained utterly frozen, unable to digest a single word of what she had just been told.
"Just what kind of person are you, Walker-kun...?"
Even as she murmured aloud in the empty classroom, nothing answered her aside from the gentle whisper of the breeze.
◇
After school.
Their meeting spot was not the official training grounds, but the rear of an old, abandoned storehouse. When she arrived, the magic sword was truly finished.
"It's done, Filiestra-san."
Wearing a bright smile she had never seen on him in class, Brendan held a pure-white, single-edged sword in his right hand. Its texture resembled porcelain, and the blade's profile was strikingly similar to the dissection scalpels Filiestra frequently used.
It was an immaculate, pristine blade without a single blemish.
Though the finer finishing touches remained incomplete, it radiated an imposing presence akin to a masterwork of art.
"Beautiful... Is this mine?"
"Yeah. It's the Filiestra-san Mark I."
"The name is, um... yeah. Let's think of one together later."
At any rate, the objective was to analyze why she was compatible when wielding his magic swords. If they could identify common factors between Brendan and Filiestra's compatibility conditions, they might uncover something new.
"Well then, let's get right to────kyaah?!"
The moment Filiestra reached out and gripped the hilt of the pure-white blade, a jolt of electricity and a violent chill coursed through her entire body.
It was decisively different from yesterday's fire magic sword.
An unsettling sensation—as if the nerves in her hand and the sword had been unilaterally fused together—sent goosebumps rippling across her skin.
"W-what is this? What's going on?"
"I tailored this one specifically for you, Filiestra-san. The weight, the length, the contour of the grip—it fits your hand much better than the last one, right? I'm glad to see you're attuning to it without any problems."
Brendan's casual nonchalance terrified her.
Experiencing a completely unprecedented sensation frightened her.
To be honest, it was deeply unsettling, yet an inexplicable sense of comfort contradicted the revulsion, drawing Filiestra in against her will.
"Could you try slashing that target? I want to observe the mutual reaction while it's in use."
A training target stood ready nearby.
It was a high-grade model capable of freely altering its hardness and toughness, ranging from the texture of raw flesh to that of heavy armor plating.
"I set the hardness to roughly that of solid rock. Give it a light slash."
The hardness of rock.
Even for Filiestra, whose magic coefficient was far above average, it was a density she couldn't break without channeling serious effort.
Feeling somewhat uneasy, she swung the sword downward just as instructed.
The blade bit smoothly into the top edge, gliding inward until it sank halfway through the target.
A mysterious tremor washed over Filiestra's entire body.
Before she knew it, a clammy sweat clung to her skin.
Was this truly a sword?
It felt as though it had been an extension of her own body from the very beginning────
"Just as I thought, it's operating without a hitch. Next, let's..."
Drip.
Just as Brendan was about to prompt her for the next step, a cold sensation brushed against their skin. Rain. Before they could even fully register it, a sudden curtain of rainfall enveloped the clearing.
"Should we head back for now?"
"Y-yes. In this downpour, we can hardly continue..."
Filiestra had wanted to pause the experiment anyway, so the timing was a relief. The sensation of the magic sword was so alien that her body felt overwhelmed. She desperately needed time to sort through her thoughts.
◇
The passing shower was heavier than expected, and by the time they made it back to Brendan's lab, both of them were thoroughly soaked.
(...Is my shirt showing through under this robe, I wonder...?)
In truth, Filiestra's concern was unfounded; the white shirt beneath her outer garment was merely a bit damp, but given the circumstances, she was feeling hyper-conscious.
'When he thinks about dirty things, he gets a nosebleed, so watch out.'
Amae had said that, but it was beyond un-magiscientific.
Fundamentally, a nosebleed occurred when the delicate blood vessels in the nasal mucosa were damaged by dryness, irritation, or trauma, leading to hemorrhage.
'When he's got a nosebleed, it's a sign he's thinking naughty thoughts, so watch out.'
Naturally, there were no documented medical cases of nasal mucosal vessels rupturing due to sexual arousal, nor was there any recognized correlation. It was only reasonable to assume her classmate had simply misunderstood something. As a licensed physician, Filiestra felt an obligation as a friend to correct that misconception.
'Bren-kun is a pervert, so watch out.'
Even so, whether Brendan himself had such inclinations was a separate matter. Up until this very moment, she hadn't given it a second thought, but looking at the situation objectively, they were a boy and a girl alone in a closed room.
The front of her robe wasn't that wet.
However, she was a bit worried about her back.
'Bren-kun is an ultra-lecherous arch-demon, so watch out.'
Amae hadn't said anything remotely like that, yet Filiestra unconsciously drew her shoulders inward, straightened her posture, and raised her guard to the maximum.
Beside her, Brendan was rummaging around for something to dry off with.
He couldn't bear to leave a gracious collaborator soaking wet.
Blacksmithing was a constant battle against heat.
Naturally, he always kept a plentiful supply of cloths on hand for wiping away sweat.
He reached for a brand-new towel stashed deep within a high shelf.
The instant he extended his arm, a heavy metal ruler leaning nearby tipped over, striking him squarely across the bridge of his nose.
"Ow..."
It hit him with considerable force, but it wasn't unbearable.
Grabbing towels for both Filiestra and himself, he poked his head out from behind the shelf.
"Filiestra-san. I've got towels here, so go ahead and use this."
"Eh? Ah, yes, thank..."
Looking over her shoulder at Brendan behind her, she froze.
Blood was gushing profusely from his nose.
"Hk...!"
She gasped.
Could it truly be that, spurred on by arousal, his mucous membranes had failed to withstand a spike in blood pressure? No, but surely that was impossible.
"Th-thank you..."
She accepted the towel with a rigid smile.
The atmosphere was hardly one where she could casually ask, "You're having a nosebleed, you know? Are you okay?", and with Brendan maintaining a completely neutral expression as if silently asserting, A nosebleed? I'm not bleeding at all, am I?, she simply couldn't bring herself to say a word.
(Still, if it's true, it can't be helped, right...? It's an involuntary physiological response, after all...)
She analyzed the situation with clinical detachment while drying her hair.
It hadn't actually been a physiological arousal response at all, but either way, it had been a complete accident this time. Filiestra decided it was best to overlook it. If it became a recurring issue, she could simply offer him some discreet medical advice as a classmate.
In the end, the rain showed no signs of stopping, so they called it a day.
At some point, Brendan's nosebleed had quietly stopped.
◇
The next morning.
"Morning, Filie-chan. How did it go?"
"Walker-kun looked at something naughty and got a nosebleed."
"See?"