HP: Hogwarts Snake

In her fourth year, Della had all the certificates she had obtained in Germany certified locally, and was exempted from almost all of Hogwarts' classes, except for Defense Against the Dark Arts, which she continued to take only after witnessing the fake Moody bullying Draco.

This small trace has remained to this day; Professor Snape's Defense Against the Dark Arts class is currently Della's only class to attend.

Professor Snape has finally gotten his wish and is now teaching Defense Against the Dark Arts.

Della sat alone against the wall in the second row. Amidst the gazes and whispers of her classmates, she nonchalantly propped her chin on her hand, absentmindedly glancing at the books spread out on the table.

“It’s good to see you, Della,” Hermione said, sitting down next to her. “Did you only have those two Defense Against the Dark Arts classes last Thursday?”

“Yes,” Della said, not surprised that Hermione had sat down next to her, but still said something symbolic, “Why did you think of sitting next to me?”

“Because we’re friends.” Hermione casually opened the book and looked at Della earnestly.

Della didn't respond to Hermione's words or gaze, but simply let out a small hum to indicate that she had heard.

Seeing Della like this, Hermione sadly turned her attention to the book in front of her.

At that moment, a long, dark shadow was thrown into the classroom from the doorway. By the fluttering outer edge, it was easy to tell that this person, whose very shadow exuded a menacing aura, was Snape.

Della looked over, wanting to see how Professor Snape was doing. The man who was still her adoptive father in law was not in the faculty section on the first day of school, and she had been keeping a low profile for the past few days. Today was the first time they had met in more than a year.

Snape walked in, his face still thin, his expression still serious, and his hair still shiny. But the emotions in his eyes, which had once impressed Della, seemed even stronger.

There was more regret, more relief, and more sorrow.

As before, his eyes held a complex look that was hard to understand.

Della and Snape exchanged a smile as they looked at each other, and then Snape called her by name.

“Oh, a familiar face that’s almost forgotten, Miss Riddle,” Snape said, his tone still sarcastic. “Should I say welcome back to Hogwarts?”

“It’s been a long time, Professor Snape,” Della said, her smile undiminished. “Perhaps you could have been a little more specific in your greetings, welcoming me back to Defense Against the Dark Arts class.”

She paused for a moment, then her lips curled into an even wider smile. "And I am very happy to be able to take your Defense Against the Dark Arts class. There is no one more suitable to be the Defense Against the Dark Arts professor than you."

As soon as he finished speaking, the students in the classroom turned their attention back to Snape and Della. They already had some impression of Snape, and now they felt even more that there was something wrong with this professor, and that Dumbledore must have made a big mistake in appointing him.

Snape ignored the students' suspicious looks; he was used to it. He simply waved to Della and said, "Since you're so happy, you can come up here and assist me in teaching this class, Miss Riddle. It'll also be a good opportunity to see if your German certificate is genuine and if your skills have declined."

“With pleasure.” Della nodded, then gracefully walked up and stood upright next to Snape.

When her gaze casually swept over the students below, the entire classroom became her territory.

Regardless of the level of her spells, at least in terms of presence, Della Riddle is no weaker than she was a year ago.

The bell rang, and Snape took out several jars containing spiders. He pushed one of them toward Della. "Today's topic is the understanding and defense against corrosive dark magic. How many spells would you like to introduce to everyone, Miss Riddle?"

"Can I only use one spider?" Della picked up the jar and examined the long-legged spider inside, which was exactly the same as the one Quirrell had given her in first year.

Snape said calmly, "Yes, only one can be used."

“Then you students should watch carefully,” Della’s smile widened as she took a few steps forward and released her hand.

The spider jar floated in the air, slowly flashing past everyone in an S-shape, and everyone could see the spider inside struggling and hitting the glass.

"I will use as many spells as possible while keeping it alive. First of all, the most classic one in corrosive black magic is the Corrosion Spell, the incantation is Rotten Bones and Flesh."

Della drew her new wand and waved it gently. The spider that had just stopped in front of Lavender Brown began to twitch in pain, and one of its long legs began to turn into pus from its tiny toe.

Lavender screamed and instinctively grabbed Ron's arm, who quickly patted her shoulder to comfort her.

Normally, Snape would have gone over and tapped Ron on the head with his book to mock him and deduct points, but today, everyone's attention was focused on Della.

"Are you scared, Brown? Next time I'll make the jar flash past you even faster," Della said considerately, patiently explaining the spell that had already made the spider twitch.

"As for the effect, as you can see, whether it's flesh or bone, it will turn into pus, and once it gets on you, it will cause irreversible damage. Generally speaking, the best solution is to cut off the flesh to save your life in order to prevent further damage."

"Of course, besides using the cutting spell which requires a lot of determination, there is also a minor spell that can resist this dark magic immediately. That spell is armor protection."

The jar reached Seamus Finnigan, who watched with a pale face as another of the spider's toes began to turn into pus. At the same time, Della raised her wand, and a dark light flashed on the leg that had begun to corrode. The corrosion stopped, and the spider saved most of its leg, but it was still in pain.

“In essence, it’s also about preventing contact, but it’s just changing the form of the flesh that could be corroded,” Della smiled and continued, “but armor isn’t a panacea. Corrosive black magic has a corresponding sand-corroding spell.”

The spider struggled again, and its half-leg began to dissipate once more, turning into a small clump of black ash that merged with the pus at the bottom of the bottle.

"This spell is not so easy to deal with. I think if you get hit by it and can't make a quick decision, you're doomed."

Della comforted the students, whose faces had turned pale, "But don't worry, this curse is extremely difficult and almost impossible to encounter."

“Alright, two legs, two spells now—” Della continued her skillful monologue, then suddenly let out a high-pitched “Ah.”

"I forgot to explain to you that using these dark magic spells is completely against the rules. It just so happens that I am a member of the Dark Magic Society and have certain teaching and demonstration privileges, so you really don't need to worry too much about it in your daily life."

Her words of comfort were of no use in calming the trembling students; they only made one thing clearer to them—

Della Riddle is extremely dangerous now, both in terms of her magical abilities and her psychological warfare.