From Azkaban to Hogwarts.

A Hufflepuff student raised his hand and asked a question—this way of communicating was quite new for these students who had just entered sixth grade, but they quickly adapted.

“That’s true,” William nodded in affirmation. “Many people know the spell, and many of you can use it, but it’s completely futile to try to find the spell in a spellbook.”

He looked at the students, "Whether you want to dive underwater, hide from the stench, or do something else, the Bubble Head Charm cannot be found in any spellbook." (Note)

"Even the magic itself is time-limited. It only becomes popular at Hogwarts or somewhere else after a period of time, then suddenly disappears, and then reappears after a period of time."

"The reason is simple: the spell itself is cursed, and it is associated with the Black Death."

William spread his hands toward the students. "I think you all know about the Black Death, right?"

"I know, Professor!"

A Ravenclaw boy raised his hand. "Nicholas Malfoy, the ancestor of the Malfoy family, who used the pretext of the Black Death to kill many of his Muggle lodgers and then blamed it on the epidemic to escape punishment. (Note)"

……

William's smile began to falter.

Ravenclaw's students are known for their extensive knowledge, and he also knows that the child called upon is good at magical history, but is this the answer he wants?

"This remains a point of contention in the history of magic. Of course, this question does exist, but that is not the point we are going to discuss."

William shook his head, easily changing the subject. Without conclusive evidence, discussing such matters in class would be nothing more than a pointless argument, and given the Ministry of Magic's current attitude, it was certain that this matter would not be investigated.

“We’re not talking about what happened during the years of the Black Death, but about the Black Death itself,” William said, raising his wand and then pointing it at the Black Lake in the air, drawing out a large mass of water and creating a giant ball of water in the air.

“Muggles have all sorts of theories about the Black Death, and the wizarding world has them too,” William said, tapping a ball of water and making ripples appear on its surface. “In fact, if you ask the Potions professor, you’ll find that they even developed a potion to cure the Black Death back then.”

"But what ultimately made those potions pale in comparison, or rather, the magic, was the Bubble Head Curse."

He waved his wand, easily casting the Bubble Head Charm on himself—the modified spell extended throughout his body, forming a thin film around him.

"This is the method my friend came up with to make raincoats; it looks really silly."

William's voice came from inside, becoming unrecognizable even to acquaintances.

“His voice was distorted because he was standing on a bubble full of air, and he looked really silly,” William said as he stepped straight into the giant water sphere and then walked out of it.

He shook his head, dispelling the bubbling curse, and reappeared before everyone.

"However, it was this very spell that saved countless wizards from the Black Death, and also shattered the dreams of that dark wizard."

"A dark wizard, professor?"

“It’s said to exist, but there’s no actual written record, so it’s not certain,” William sat down again. “I heard it from my teacher. It’s said that this magic originated from a rat that was specially raised and cursed by a dark wizard. That dark wizard released it, attempting to enhance his own magical power and thereby achieve immortality and change the world…”

"But such behavior was eventually curbed. With the Bubble Head Curse, wizards were basically kept away from the Black Death, and the hiding place of that dark wizard was also found."

"The wizard who invented the Bubble Head Curse eventually defeated the black wizard who used curses and rats to develop the Black Death, but he and his invention were cursed as a result and disappeared from recorded history."

"What a pity..."

The students below murmured with emotion, but William paid no heed to their interruption.

"But the curse does not diminish the greatness of this spell. I personally think it is the most practical auxiliary spell among all self-defense spells. Its strength lies not in its offensiveness, but in its adaptability."

William waved his wand, writing glowing letters in mid-air.

"In most extreme environments, the Bubble Head Charm can provide the user with the most comprehensive protection—a house ablaze with flames, a lake or sea, a deep cave, a volcano crater hiding various precious materials..."

William gave a series of examples, then paused to let the students imagine the extreme scenarios themselves—he was now quite adept at this and wouldn't lose control and blurt out knowledge related to smuggling.

"If you master this spell, you can even use it to provide some protection. Although it's better than nothing, if your spell is powerful enough, it can even help you deflect some attacks."

"Of course, each spell has its own unique use. Don't expect it to do everything that the Ironclad Spell does; that's unrealistic."

"Alright," William clapped his hands. "That's all for the theoretical introduction. Next, I'll give a brief introduction to the spell. Those of you who have already learned it, please wait a moment. While the rest of you are familiarizing yourselves with the spell, we can help you practice."

He waved his wand, and one after another, clumps of water were pulled up from the Black Lake and fixed into spheres, which were then displayed before everyone.

"Don't worry, we have ten testing sites, and everyone will get a turn."

"Students who have mastered the material before get out of class ends are fine, don't worry. Okay, concentrate and memorize everything from now on, every single detail!"

-

"Today's class was fantastic!"

"That's it!"

After class, the sixth-grade students formed teams and began their return to the castle—the self-defense lesson, which ended in the sunshine and on the grass, made them feel that there was absolutely nothing wrong with choosing the advanced class.

"How did it feel to enter that large water mass?"

"It's amazing! Being completely enveloped in cool water makes the sky look different!" exclaimed a student who had already mastered the head-soaking spell. "Honestly, I never thought this magic could be used underwater!"

"Be careful, the professor said that if the spell isn't strong enough, it's easy for the magic to fail in water. Don't even think about going to the Black Lake!"

His friend offered a careful reminder.

"Don't worry, I won't—" He shook his head. "You're the one who needs more practice. I think the professor will only give you another week of lessons at most. If your magic still doesn't meet the standard next time, then you really can't try."

"It's alright, it's just summoning a water sphere from the water and then enveloping the person, right?"

Another child grabbed his friend and ran towards Black Lake, shouting, "I can do it too! I'm almost an adult!"

He waved his wand. "The professor can create ten at once, so it's not unreasonable for me to create one, is it? It's just a levitation charm, a polymorph, and a little magical skill. My polymorph is an E-rank!"

He manipulated a large mass of water to fly up, and then it condensed into the shape of a water ball.

"It's that simple—ah!!!"

The student manipulating the water sphere laughed as he showed off his work. Then, imitating William, he poked it, and the polymorph spell holding the water sphere changed, wrapping around his finger and swallowing the little wizard who had cast the spell.

"Gurgle, gurgle, help, gurgle, life!"

Shouts came from the water clump, then it dispersed, splashing water everywhere like a punctured water balloon.

"Cough cough... This is much more difficult than I thought... What other magic did the professor use? Levitation and Polymorph are far from enough!"

"Pah... Where did this shrimp come from!"

The sorcerer struggled to his feet, then looked at his friends who were laughing hysterically, thought for a moment, and without saying a word, pulled a large ball of water from the lake and threw it directly at his friends.

-

"The first class went relatively smoothly."

William nodded, satisfied with the student's performance.

After all, they were students I had taught for a year, so adding a little extra homework didn't put any pressure on them at all.

Unfortunately, although the Ministry of Magic passed all the students, many of them could only be considered to have passed the exam; their spellcasting skills were still far from sufficient.

Of course, he can say without any shame that the average level of the students he taught is far higher than that of the students still in school—even for academic superstars like Percy and Hermione, a cramming session would be beneficial.

But it's okay, there are sixth and seventh grades after fifth grade. The OWLs exam is only once. Once you get the certificate, you can make up for the lack of spellcasting experience and expansion training through intensive training.

'However, this isn't entirely my credit. Because of that damned curse, the students' basic defensive magic is absolutely terrible; such a result isn't something to boast about.'

He patiently reviewed the day's interactions and, after confirming that everything was alright, headed straight for Hagrid's house.

We made an appointment this morning; I'll help Haige with the project today.

Although this test might be harder than last year's fifth grade—and after what happened this morning, William didn't feel he could offer much effective help.

Humans are narcissistic, and wizards are no exception.

Basically, everyone appreciates what they believe is right, and then unabashedly believes that it is good.

As for the seemingly counterintuitive fact that people who frequently lie and cheat like to befriend kind people—they all know it's true, but they can't help but feel that it benefits them.

Hagrid was much older than William, and although he was kind, William didn't think he could change Hagrid's mind.

In fact, the old professor and Hagrid had a better relationship than Dumbledore and Hagrid—Hagrid admired Dumbledore, but he got along best with the old professor.

As for what William overheard last year about Hagrid talking about keeping dragons while drunk, Hagrid genuinely regretted it and felt sorry for Dumbledore. However, when talking about the old professor, he could still say with guilt towards Dumbledore, "Haha, I should have shown the dragon to the professor back then. He must have admired Norbert's teeth!"

“What a headache,” William said as he finished packing and saw Hagrid’s house in the distance. “I hope he really did it.”

-

"Hagrid!"

William called out Hagrid's name and waited in front of the hunting grounds.

"William, you're here!"

Hagrid's voice was as loud as ever, "I've just changed my clothes, what do you think!"

He opened the door while shouting, and William, with his back to the sunlight, immediately saw the clothes that the half-giant had carefully prepared.

Although he had prepared himself mentally, Hagrid's appearance still startled William.

'Is this Hagrid? Aside from being a bit too tall, I'd believe him if he said he borrowed some clothes for the blind date…'

The giant before them was dressed in an enormous wizard's robe, and his hair and beard were styled to be incredibly shiny and smooth by some unknown means. If it weren't for his enormous size, he could easily be mistaken for a farmer on a blind date.

"Not bad, William."

Hagrid laughed, clearly pleased with his carefully chosen attire.

However, upon hearing this smile, William immediately frowned.

With that smile, you think you can manage students?

It's no wonder they get bullied by troublemakers...

Chapter 273 Another Method of Teaching

"Don't laugh, Hagrid."

"It's the same old problem. You need to be serious, Hagrid. You're not chatting with a friend; you're imparting your knowledge to your students."

In Hagrid's cabin, William once again offered suggestions for improvement, but they had almost no effect.

It's hard to stop Hagrid from laughing—he radiates his kindness from time to time without any attempt to hide it.

“We need to think of something else, Hagrid,” William finally gave up on his initial idea after more than half an hour of failure. “If we can’t intimidate the students with our expressions, then we have to make them marvel at your lessons.”

Among the professors at the school, Professor Flitwick did just that. Logically speaking, given Hagrid's size, he didn't need to do that at all, but now he could only make up for it with something else.

"How's the wand ban going? What's the approval process like? Are you now permitted to use your wand to cast spells?"

William looked Hagrid up and down, still thinking about making a final attempt to salvage the situation.