The Irregular at Magic High School: Everyone Loves My Brother?!

Despite the student council and disciplinary committee's chaos, Tatsuya doesn't head straight for rest upon returning home. Instead, he descends to the basement, where the Shiba household houses a CAD calibration device rivaling those in government or research facilities.

Why such equipment exists in a private home is a question for another time.

"Brother, it's Miyuki. May I come in?" Miyuki's voice echoes softly.

"No need to ask. Come in," Tatsuya replies.

No matter how busy, Tatsuya never brushes Miyuki off. She always seeks permission to enter the basement, and he, now accustomed, responds without hesitation.

"Pardon me," Miyuki says. "Could you adjust my CAD?"

"Didn't we do that three days ago?" Tatsuya asks. "Settings off?"

Usually, adjustments happen weekly, so something significant must have prompted this. Miyuki flusters. "No, no! Your adjustments are always perfect! It's just… I want to tweak the restraint spells."

"Restraint spells?" Tatsuya raises an eyebrow.

"I want more variety in interpersonal combat," she explains.

Miyuki isn't adept at minimal-damage neutralization, like Tatsuya demonstrated today. Her strength lies in overwhelming opponents with raw magical power, a direct approach Tatsuya believes suits her best.

"Is that okay?" she asks, eyes upturned, glistening with earnestness.

Of course, Tatsuya could never refuse her, especially not with such a look. "It's fine," he says, placing a hand on her head. "Let's sort through your registered activation sequences."

"First, we'll measure," he adds.

CAD adjustments require measuring the user's magical capacity. Typically, a headset suffices, but the Shiba's advanced device involves a full-body scan on a bed. Tatsuya's clinical gaze assesses Miyuki's abilities as she removes her gown, unfazed by her figure. Once complete, his focus shifts to the data, diving into work. Miyuki slips her gown back on, permitted by Tatsuya, but a flicker of discontent clouds her mood.

As always, her brother shows no interest in her physically. It's expected, yet today her heart feels unusually restless. Leaning forward, she drapes her arms around Tatsuya's neck from behind, a bold move for her.

"You're unfair, Brother," she murmurs.

"Miyuki?" Tatsuya's voice betrays rare unease—not the flustered panic of a typical teen, but confusion over her actions.

"I'm so embarrassed, yet you're always so calm," she continues.

"Uh, Miyuki?" he tries again.

"Am I not even a woman to you?" she presses.

"It's not that…" Tatsuya stammers, struggling to find words to appease her. She's his sister, not "a woman," but explaining that eludes him.

"Do you prefer Saegusa-senpai or Watanabe-senpai?" Miyuki accuses. "You were awfully chummy with them at committee headquarters today."

"You saw that?" Tatsuya asks, inadvertently confirming her suspicion.

Miyuki's anger flares. "So it's true! They're both beautiful, aren't they?"

"Whoa, Miyuki, you're misunderstanding!" Tatsuya protests, sensing the tension spike.

Her CAD is already in hand, activation sequence primed. "Time for punishment!" she declares.

"Gah!" Tatsuya yelps as her signature cooling spell hits, blasting him from his chair to the floor.

For most, this could mean serious injury, but for these siblings, it's a familiar scene.

"Good morning, Brother," Miyuki says lightly.

"Did I do something to upset you?" Tatsuya groans, unscathed.

"Sorry, I got carried away," she replies, echoing his earlier excuse to Mari. He takes her offered hand, a wry smile on his face.

"Give me a break," he mutters, amused by her antics despite the magical assault.

The next morning, Miyuki writhes in her bed, mortified. She'd thought her boldness—clinging to Tatsuya in barely a slip—was cute, but now embarrassment consumes her.

"This isn't love. This isn't love…" she chants, steadying herself. Springing up, she flings open the curtains. "For Brother's sake, I'll make a delicious breakfast today!"

Tatsuya's at Yakumo's temple, as usual. It's rare for Miyuki to rise first, like two days ago. Though the temple offers meals, Tatsuya always returns hungry, and Miyuki never skimps on breakfast prep.

"Making Brother happy is my reward," she murmurs to the empty room, her expression undeniably that of a devoted sister. Anyone witnessing it would agree.

Earlier that morning, at the Yotsuba main house, Mayo converses with Hayama about the anti-magician movement.

"Students can be swayed by such causes," Mayo says. "How's First High faring, with Miyuki and the others?"

"There's some contamination from 'Blanche's faction,'" Hayama replies. "Shall I arrange something?"

"No need," Mayo cuts in with a confident smile. "If it comes to it, there's a use for it. Besides, Tatsuya's there. We don't need to act."

"But Tatsuya-dono…" Hayama hesitates.

"He's got his baggage, sure, but he's not fragile," Mayo insists. "Whatever my sister thought, Tatsuya's vital to the Yotsuba."

"Making an enemy of him isn't wise," Hayama concedes.

"Only Tatsuya can rein in Miyuki," Mayo adds. "And frankly, only he satisfies me."

"Er, yes," Hayama stammers, masking a sigh. If Mayo's subordinates heard her, it'd cause a stir, but she only speaks this way around Tatsuya, Miyuki, and him. Neither she nor Tatsuya betray such openness otherwise.

"So, how will Tatsuya and Miyuki satisfy me?" Mayo muses. "What do you think, Hayama?"

"I haven't the faintest idea," he replies.

"Nor I," Mayo laughs. "Very well. Tea, please."

Satisfied, Mayo drops the topic. Hayama bows and prepares her tea with practiced precision, his composure unshaken. This trust, both he and Tatsuya know, is why Mayo reveals her true self to him.