Harry Potter and the Ambitious Girl

No matter how heavy the rain, the Hogwarts Express never stops.

As the new school term began, the train carried many students to Hogwarts, each filled with either excitement or anxiety. Inside one of the compartments, Mirabel sat munching on a cauldron cake, swaying gently with the train's rhythmic vibrations.

Outside the window, the rain continued to pour, making it too dark to enjoy the view. Across from her sat Edith, her Slytherin classmate, savoring a pumpkin pasty.

They were the only two in the compartment. Mirabel's presence alone was enough to intimidate other students from even approaching.

Swallowing the sweetness she had grown tired of, Mirabel complained.

"This train's menu never changes, no matter when you ride it. It's not bad, but I'm getting sick of just sweets."

"Well, it's not like the train gets used often," Edith replied.

The taste itself wasn't bad—in fact, one could argue it rivaled that of specialty cake shops.

But humans can't live on sweets alone. Desserts are meant to complement meals, not serve as the main course.

It was only natural for Mirabel to be irritated at the lack of substantive food on the train.

"By the way, do you know who's teaching Defense Against the Dark Arts this year?" Edith asked.

"...Apparently, it's a man named Remus Lupin. I heard he's in one of the forward carriages."

"Do you think this one will last the whole year?"

Edith's concerned remark echoed the worries of nearly every student.

Ever since Edith and her classmates started at Hogwarts, no Defense Against the Dark Arts teacher had lasted more than a year.

In their first year, it was Quirrell; in their second, Lockhart. Both were gone after a single term.

This track record had earned the subject a reputation as the "cursed position."

"No idea," Mirabel replied nonchalantly as she opened the cap of a water bottle.

She took a sip of tea to quench her thirst.

Dissatisfied with the train's sole drink option—pumpkin juice—she had taken to bringing her own beverages.

"Well, at least he can't be worse than Lockhart."

According to "The Legacy," a collection of trusted magical knowledge, Lupin was expected to be an exceptional teacher.

This was the year Harry would master the Patronus Charm, a high-level spell, under Lupin's guidance.

Considering that, Lupin seemed far more promising than any of his predecessors.

"You don't seem all that interested," Edith remarked.

"It's not that I'm uninterested," Mirabel replied. "But right now, my mind's on Hogsmeade."

"...You're just thinking about food, aren't you?"

"What else is there to think about?"

Hogsmeade was a small village exclusively accessible to third-year students and above.

It was likely the only place in the world entirely free of Muggles, catering solely to the wizarding community.

The village offered a variety of goods, from common sweets found in the Muggle world to unique magical treats, magical tools, and prank supplies.

Despite her complaints about the train's lack of variety, Mirabel actually had a sweet tooth and had been eager to visit Hogsmeade.

As they chatted, the train began to slow down.

Edith glanced out the window. "Looks like we're about to arrive."

"...No, we still have at least an hour to go," Mirabel said.

The Hogwarts Express wasn't supposed to arrive for another hour at the earliest.

There was no chance the train had been running unusually fast today—if anything, the rain should have slowed it down.

Realizing this, Edith looked around with a serious expression.

From various compartments, other students began peering out, puzzled by the unexpected stop.

Eventually, the train came to a complete halt, and even the lights inside went out.

"What's going on? Could it be some kind of event organized by the school?"

"No, I doubt it's something like that," Mirabel said.

She lit her wand with a Lumos spell and stepped out of the compartment.

There, she ran into Hermione, Ginny, Neville, and Harry, who had emerged from the neighboring compartment.

It seemed they were riding the same carriage.

Seeing Mirabel, Hermione approached with a bewildered look.

"Beresford, do you know what's going on here?!"

"Who knows," Mirabel replied indifferently.

Of course, Mirabel knew the cause of this phenomenon from her wealth of knowledge.

However, she had no obligation to enlighten them, nor was she the type of girl to indulge in needless charity.

Besides, the answer would soon reveal itself. There was no need to waste energy on explanations.

Correction—not "will reveal," but rather, "has already revealed itself!"

"Perhaps you could ask them," she said, jerking her thumb toward the train's entrance.

"What...?"

Following her gesture, they saw it: a towering black figure cloaked from head to toe, its form nearly brushing the ceiling.

Its face was obscured by a hood, and the only visible part of its body was a single arm—a cold, pallid gray appendage marred by vile scabs, as if it had rotted underwater.

"Mirabel... Wh-what is that thing?"

Edith clung tightly to the edge of Mirabel's robe, her voice trembling.

Watching her pitiful state, Mirabel mused that a friend of hers shouldn't cower so easily, but since this was Edith's first encounter with such a creature, she'd let it slide—this time.

"That, Edith, is a Dementor. A soul-eating wretch. The vilest creature on this earth.

Or, if it makes more sense, think of it as a prison guard for Azkaban."

"Th-that's a Dementor...?"

As they whispered, the Dementor emitted a rattling breath and inhaled deeply.

At that moment, an unbearable chill swept through everyone present, like an icy claw raking down their spines.

An oppressive, suffocating misery weighed heavily on them, as though they'd never feel joy again.

Ginny trembled uncontrollably. Neville shrieked.

Hermione froze in fear, while Edith clutched her mouth and fell to her knees.

But the worst was Harry, who fell off his seat, convulsing violently on the floor.

(So, this is a Dementor—the most loathsome creature... How utterly repulsive.)

Wiping the cold sweat from her brow, Mirabel glared at the Dementor, her expression a portrait of absolute disdain.

She didn't care what happened to anyone else. But she found the creature's very presence insufferable.

It had cast its predatory gaze over everyone in the compartment, herself included.

That was the real offense. That was unacceptable.

This thing dared to regard her—Mirabel Beresford—as prey?

Unforgivable. She was above such contempt! The world revolved around her. Others cowered, she ruled.

She would educate this vile being on the proper hierarchy.

"Let go, Edith," she snapped.

Shrugging off Edith's grip on her robe, Mirabel took a step toward the Dementor.

There wasn't an ounce of fear in her expression. Why should there be?

It wasn't arrogance—it was confidence. A hunter feels no fear before their quarry.

"You filthy, inferior creature," she spat. "Who gave you permission to sully my presence with that hideous form?"

Her voice brimmed with overbearing arrogance, but the Dementor remained unperturbed.

It let out a faint, guttural moan and began to drift toward her.

Its audacity was intolerable. To approach her without even acknowledging her words? Such insolence was beyond forgiveness.

"Hmph! It seems you need a lesson!"

She raised her wand, slashing it through the air.

"Invaderent Patronum! Attack, my guardian spirit!"

In a flash, a gleaming silver figure emerged, slicing cleanly through the Dementor's outstretched arms.

The spell she cast wasn't a mere Patronus charm. No, it was her own creation—a combat-oriented Patronus, designed not just to repel but to destroy.

Knowing Dementors would appear in her third year, Mirabel had, of course, prepared countermeasures.

This spell was crafted by her and her alone—for the sole purpose of annihilating Dementors.

In the presence of this power, they were helpless. Invincible. Absolute.

"~~~?!"

"Oh? Even filth like you can feel pain? That's a useful discovery," she sneered.

Watching the creature writhe in agony, Mirabel allowed herself a small, sadistic smile.

Yes, this was the natural order. This was how things should be.

No one could look down on Mirabel Beresford. Not humans, not creatures, not anyone.

She alone ruled. She alone held the power to dominate, to trample, to destroy.

Regardless of the foe. Regardless of the circumstances. No exceptions.

"Well then, where should I tear off next? Your chest? Your stomach? Or should I just take your neck and end it quickly?"

"!!?"

"Heh, so you're not just some mindless creature acting on instinct… What's this? You actually have fear. Excellent. Be more afraid. Tremble. That's exactly what I like to see."

Completely confident in her dominance, Mirabel advanced a step or two, closing the distance like a predator playing with its prey, her tongue briefly licking her lips in delight. Watching this, Hermione recalled the nightmare from the previous year. It was the same dangerous air Mirabel exuded when she toyed with the basilisk.

Her usual composed demeanor was nothing but a mask concealing her true nature. It was only when tormenting others that this golden-haired girl revealed her true self—her terrifyingly dangerous self! Released from the chains of reason, the "Monster of Slytherin" raised her wand high, her golden eyes glowing fiercely, her cheeks flushed with a faint red.

There was no one left to stop her now. No one to save the Dementor. And as the unleashed girl swung her wand downward…

A large hand reached out from the side and caught her arm.

"Stop it. Killing one of Azkaban's guards would cause serious trouble."

The hand belonged to a shabby-looking man dressed in a patchwork robe. His light brown hair was streaked with gray, and his pale face gave the impression of someone ill. Yet, the strength in his grip and the firmness in his reprimanding gaze were undeniable.

This man was none other than Remus Lupin, the new Defense Against the Dark Arts teacher for the year.

Mirabel studied his face for a few seconds before letting out a sigh of irritation. Reluctantly, she lowered her arm.

"Self-defense, I would argue."

"Maybe so, but cutting off its arms is one thing. Killing it would be excessive."

The fun was over, leaving Mirabel feeling thoroughly disappointed. She stowed her wand with a bored expression and helped Edith, who was slumped on the floor, back to her feet. She left dealing with the Dementor entirely to the shabby man—Lupin. Since he was so insistent, he could take responsibility.

Lupin sternly told the Dementor, "No one here is hiding Sirius Black under their cloak. Leave." However, the creature didn't move, seemingly enraged about having its arms severed. But Lupin dismissed it with, "You brought this upon yourself," and forced the Dementor to retreat with a Patronus charm.

Impressive—he certainly lived up to his claims.

"Eat this, Rynagrl."

"...Chocolate frogs?"

"You'll feel better."

Mirabel pressed a chocolate frog into Edith's hands and bit into one herself. Warmth spread to her extremities, and her body quickly regained its usual state. Edith followed suit, her complexion improving noticeably. The effect was immediate.

Looking over at Harry and the others, they were also receiving chocolate from the shabby man, their faces steadily regaining color.

"I'm surprised. You seem to know how to deal with Dementors," the man commented in astonishment.

"Yes, to some extent," Mirabel replied curtly, already chomping down another piece of chocolate.

To her, this was basic knowledge. Her father, Heathcote Beresford, was a specialist in combating dark wizards—a renowned Auror. And her mother was no ordinary figure either.

Her mother, Maeve Beresford, was the deputy headmistress at Durmstrang and a professor of the Dark Arts. Mirabel had been trained in dark magic from a young age, almost like abuse disguised as elite education.

Given such a background, how could Mirabel not possess this level of knowledge?

Eventually, the train resumed its journey, and they arrived at Hogwarts without further incident. As usual, the Sorting Ceremony for new students was conducted, and the new faculty members were introduced.

The Defense Against the Dark Arts post went, as expected, to Remus Lupin. Meanwhile, Care of Magical Creatures was assigned to Hagrid, the groundskeeper—a decision Mirabel saw as a glaring mistake.

Sure, Hagrid was loved by animals and had a knack for taming them. He was also a good-hearted man. But Mirabel couldn't see him as suited to teaching. Still, she decided to give him a chance, though she doubted he would meet expectations.

And so, another chaotic year began.

Noticing a small part of herself looking forward to it, Mirabel couldn't help but smirk.

The next morning, when Mirabel went to the Great Hall for breakfast, the Slytherin table was unusually lively.

At the center of the commotion, Malfoy was pretending to faint, drawing laughter from his peers.

There was no need to guess who he was mimicking—it was obviously Harry Potter, who had fainted in front of the Dementors.

Given that Harry had led Gryffindor to victory two years in a row, he was thoroughly despised by the Slytherins. His disgrace, however minor, was cause for celebration.

"…He was terrified of the Dementors himself, probably enough to wet himself," Edith muttered irritably as she took her seat.

Seeing this, Mirabel smirked, raising an eyebrow.

"My, aren't we in a sour mood, Laynagle. Have you taken a liking to Potter?"

"It's not… anything like that," Edith replied.

"Really? Last year, you seemed to be getting along with them just fine," Mirabel said as she poured milk over her cereal, clearly enjoying herself.

She wasn't wrong—last year, during the period from Christmas to the end of term, Edith had indeed worked with Harry and Hermione. While it was a collaboration to uncover the truth about the Slytherin monster, it couldn't be denied that a sliver of camaraderie had developed.

"Well, if it's upsetting you, I could shut him up," Mirabel offered.

"No, it's fine… You're ruthless, after all," Edith replied.

To Mirabel, Malfoy was an annoying nuisance at best. Silencing him wouldn't bother her. However, knowing Mirabel's lack of restraint, Edith declined, turning her attention to a nearby plate of bacon and eggs.

When she pierced the yolk of her egg with a fork, the creamy yellow center spilled out, staining the white. A bite of the mixture filled her mouth with its rich flavor.

"But why do you think Harry fainted?" Edith asked, curiosity evident. "He doesn't seem like the type to have a weak heart."

"Weak? On the contrary, he has one of the strongest minds there is," Mirabel said, crunching on her cereal. "Aside from myself, his mental toughness surpasses anyone who was there."

"Then why?"

"Dementors feed on happiness and joy, leaving only the worst memories behind. For someone like Harry, who's lived through such tragedy, fainting is only natural."

Mirabel's explanation was matter-of-fact. In the face of Dementors, mental fortitude wasn't the key factor. It was the weight of one's past.

Someone like Malfoy, who had led a spoiled, indulgent life, would barely feel their effects. On the other hand, had he endured even half of Harry's experiences, he might have gone mad instead of fainting, Mirabel reasoned.

"How do you avoid fainting?" Edith asked.

"The quickest way is to use the Patronus Charm, though it's a high-level spell that most people can't handle."

"That spell you used on the train?"

Mirabel grinned mischievously at Edith's question, tearing into a piece of buttered bread.

"What I used was a modified Offensive Patronus—a version I've developed myself."

"…Didn't you just say it's a high-level spell? How did you already make it your own?"

"Because there's nothing I can't do," Mirabel declared confidently, dabbing her mouth with a napkin.

Her meal apparently finished, Mirabel stood up, while Edith, looking both exasperated and resigned, continued eating her custard pudding.

"Do you think I could learn the Patronus Charm?" Edith asked.

"It'll be tough. If you can't master the basic Patronus, there's no point in trying," Mirabel explained.

The spell Mirabel used wasn't just advanced; it was a unique evolution of an already high-level charm. Designed solely for Mirabel's unparalleled talent, it wasn't something others could easily learn or use.

"Then teach me the basic Patronus Charm," Edith said.

"Hmm. I wouldn't mind teaching you, but whether I'll have the time is another matter…"

"What's going on?" Edith asked, setting down her pudding.

Mirabel took a sip of tea, then made her announcement—a statement that would serve as a beacon of hope for Slytherin and a nightmare for Gryffindor.

"Last year, Marcus Flint begged me to help Slytherin finally beat Gryffindor.

I wasn't keen on the idea, but I can't deny that losing year after year is tiresome.

So, just this once, I've decided to lend them my strength."

"Let's utterly crush Gryffindor," Mirabel said with a confident, triumphant smile.

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