With Peter Pettigrew's capture, the Dementors stationed outside Hogwarts withdrew, returning to their posts guarding Azkaban. The weather around the castle returned to its usual unpredictable pattern—one moment sunny, the next pouring rain—but at least it wasn't the constant dreary drizzle anymore.
Lupin, now armed with a method to revert to his human form, was brimming with enthusiasm. He threw himself into teaching the young witches and wizards with renewed vigor.
"Today's Defense Against the Dark Arts lesson is about countering dark magic—specifically, the Serpensortia spell."
The curriculum was shifting from dealing with dark creatures to confronting dark magic itself. After all, the number of dark creatures Lupin could access was limited. He could handle creatures up to a 4X danger rating, but 5X-level ones, like the elusive Voldibat (whose name bore an unfortunate resemblance to Voldemort's), were beyond his reach. Those creatures were so rare that the wizarding world was debating whether to list them as extinct.
The Basilisk had nearly made that list once.
Learning to counter dark magic was a core component of Defense Against the Dark Arts, divided into two main areas: defending against dark magic as it's being cast and undoing its effects after it takes hold.
The first area, defending against dark magic during casting, was more accurately about protection. Most people assume that if dark magic exists, there must be "light magic" to counter it. But in the wizarding world, there's no such thing as "light magic." Spells that protect against dark magic are collectively known as Protective Charms.
The Patronus Charm is one of the advanced ones, and the ancient spell Lily used to protect Harry at the cost of her life also falls under this category. Of course, combat is fluid, and strategies shift depending on the situation—there's no one-size-fits-all approach.
If your magical power is strong enough, you might not even need a Protective Charm. You could use something as simple as Expelliarmus for both attack and defense.
Under Lupin's guidance, the students learned a variety of Protective Charms.
The second area focused on undoing the effects of dark magic after it's been cast—through Counter-Curses.
Most spells, including dark magic, have a corresponding Counter-Curse. A skilled Defense Against the Dark Arts master must be proficient in these. For example, the dark spell Sectumsempra, which causes uncontrollable bleeding and wounds that are nearly impossible to heal, has the Counter-Curse Vulnera Sanentur. Without knowing the right Counter-Curse, injuries from dark magic (or jinxes) are incredibly difficult to treat.
That's why, despite potions that can regrow bones, some wizards still lose limbs—because they couldn't identify the dark spell or its Counter-Curse.
When multiple dark spells hit at once, they can cause unpredictable mutations, making treatment even harder.
It's worth noting that a Counter-Curse isn't like flipping a switch to turn off dark magic. It's a way of reversing the spell's effects, the most effective method to undo the damage caused by dark magic.
In short, every great Defense Against the Dark Arts master is a master of Counter-Curses and protective magic.
The young witches and wizards soaked up Lupin's teachings like sponges, their progress so rapid it was jaw-dropping. Even Lupin himself remarked that if he taught them for another year or two, they might drain him of every bit of knowledge he had.
With Dudley and the Discipline Committee keeping everyone in line, the third-years at Hogwarts were in a frenzy of studying. It wasn't just Defense Against the Dark Arts—every subject was a battlefield. Even the fifth-years preparing for their O.W.L.s were starting to feel outpaced by these relentless third-years.
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During the Care of Magical Creatures class, while the other students were happily observing unicorns, Hagrid quietly pulled Dudley aside.
"Dudley, I've done it! I've successfully bred the third generation of shelled carnivorous slugs!" Hagrid announced.
The latest batch of carnivorous slugs had been successfully bred under the expertise of Hagrid, the master of magical creature crossbreeding. The new generation had already hatched.
Hagrid was over the moon. His obsession with magical creatures was almost unimaginable, and the thrill of creating a new species was, to him, pure bliss.
"Their shells are now fully defensive. I think they're exactly what you wanted," Hagrid said, lifting the lid of a wooden box to show off his achievement. The shelled carnivorous slugs had grown four or five times larger than before, now slightly bigger than the average person's hand.
This third generation was barely recognizable as carnivorous slugs anymore—they were evolving into an entirely new species.
"What do you think? Pretty great, right? Oh, and there's more good news!" Hagrid continued, barely containing his excitement. "That Manticore we had? It finally got several Fire Crabs pregnant. In a little while, we'll have a whole new species! I can't wait to see what kind of babies they'll be!"
Hagrid's enthusiasm was infectious. Compared to the shelled slugs, the pregnant Fire Crabs thrilled him even more. Perhaps it was his giant blood, but Hagrid had an instinctual fondness for dangerous creatures. The more perilous, the cuter they seemed to him.
Being a half-giant, with thick skin, high physical defense, and incredible strength, Hagrid could overpower 99% of magical creatures with raw force alone. Every beast in the Forbidden Forest had, at one point or another, been on the receiving end of his fist. How else could he bring new, ferocious creatures to every class?
"Den Den Mushi," Dudley said.
"What?" Hagrid, caught up in his excitement, hadn't caught it.
"From now on, these shelled carnivorous slugs will be called Den Den Mushi. That's the name I'm giving them," Dudley clarified.
He picked up one of the creatures for a closer look. Under Dudley's intense gaze, the Den Den Mushi seemed to sense danger and retreated fully into its shell, refusing to come out.
Dudley weighed it in his hand. These toothy magical snails were finally ready to be transformed into true Den Den Mushi. Whether the transformation would succeed, though, was another question.
"Den Den Mushi? That's a weird name. I was gonna call 'em Shell-Shells," Hagrid said, his face falling with a touch of disappointment.
"Dudley, what's a 'telephone' anyway?"
It wasn't Dudley's imagination—ever since he'd bested Hagrid in a fight, the half-giant had taken a keen interest in him, even going out of his way to be friendly. There was an odd sense of camaraderie there, though Dudley was pretty sure he hadn't unlocked some kind of "giant affinity" skill.