At Hogwarts, the story begins with deconstructing Avada Kedavra.

Hogwarts Library.

For most students, this is a place they only come to when they're rushing to finish assignments or when the damn finals are approaching.

But for Lucien, this might be the best place in the castle, provided that those living fossil professors don't share all their knowledge.

The restricted book section is a popular tourist attraction at Hogwarts.

After all, this is what Ms. Ravenclaw said:

Knowledge is a wizard's greatest treasure.

Mrs. Pince was an extremely strict librarian. She guarded every book like a dragon guarding its egg, and would chase after students who ate snacks on the books with a feather duster.

But when facing Lucien, her attitude was surprisingly tolerant.

Because he showed an almost pious respect for books.

Before each book, he would wash his hands; when turning the pages, he would not fold the corners, but use a transparent magic bookmark; and if he saw that the spine of the book was coming unglued, he would even use repair magic to glue it back on.

For a librarian who deals with unruly children all day long, Lucian was an angel.

At this moment, Lucian was sitting in the corner by the window, with "The Origins of Medieval Alchemy," "The Construction and Deconstruction of the Soul," and a thick book as heavy as a brick, "An Analysis of Advanced Runes," piled on the table.

Sunlight streamed through the towering stained-glass windows, casting dappled shadows on his profile.

Most of the books in Hogwarts are precious, not only because of their rich historical memories, but also because most of them are manuscripts or hardcover editions, carrying fragments of the authors' ideas and threads of memories.

In his mental vision, the words on the pages flow, and his thoughts connect with the author; he turns the pages extremely quickly and efficiently.

"This memory transfer magic... is too inefficient." Lucian closed a book about memory spells and sighed softly. "Does it even need a wand to extract the silver threads? Why not just establish a mental link directly?"

He picked up his quill pen and jotted down his inspiration in the thread-bound notebook he always carried with him:

[Topic 32: Wireless Improvement of "Mind Capture and Thought Interception"—Referencing the Principles of "Telepathy".]

"What are you writing? That doesn't sound like English."

A voice came from above.

Lucian didn't look up; his pen continued to move steadily, recording something.

"If I were you, I wouldn't float right above my ink bottle."

The owner of that voice was clearly taken aback.

That was Barrow the Blood, the ghost of Slytherin. He usually only frightened newcomers with his dead-fish eyes or let out chilling groans. Few dared to speak to him like that.

Barrow descended slowly, his robe stained with silver blood piercing through the tabletop, the bone-chilling cold causing a thin layer of frost to form on the ink.

"Aren't you afraid of me?" the ghost asked ominously.

Lucian finally raised his head, took off his glasses, and rubbed his temples.

"Why be afraid? You are just a remnant image of a soul, a weak projection of consciousness onto the real world. In Eastern terms, you are a 'bound spirit'."

"A bound...spirit?"

“That’s right. Besides, your soul structure is very unstable right now, and energy is constantly leaking out from the wound in your chest.” Lucian pointed to the bloodstains on Barrow’s robe. “That’s why you need to draw fear from people to keep your physical form from dissipating. A very pathetic way of living.”

Barrow roared angrily, the temperature around him plummeted, and the books on the shelves began to tremble.

"But I can help you fix that vulnerability."

Lucian interrupted him, "While I can't bring you back to life, or even free you—that requires you to let go of your obsessions—I can make you less...air-leaky. That way you won't have to suck in negative emotions like a vacuum cleaner all day."

Barrow's roar caught in his throat. For centuries, no one had ever spoken to him like that. People either feared him or avoided him.

"How?" the ghost's voice lowered.

Lucian drew a complex incantation in the air and then gently touched it to Barrow's illusory chest.

"Sizzle—"

The talisman merged into his spirit, like a patch, sealing the leaking energy.

Barrow stared in astonishment. For the first time in centuries, he no longer felt that constant, wind-blown weakness. His spirit even seemed to solidify a little.

"What...what kind of magic is this?" Barrow asked, his tone filled with awe.

"A little trick." Lucien put his glasses back on. "In exchange, I need you to do me a favor."

"Speak." Even the ghost of Slytherin has principles.

"Keep an eye on Professor Quirrell for me," Lucien said in a low voice. "Nothing much, just tell me where he goes every night, especially... when he smells of anything other than garlic."

Barrow nodded, gave the first-year student a deep look, and then disappeared through the wall.

In this castle filled with cameras (portraits) and listening devices (ghosts), controlling these informants is equivalent to controlling the intelligence network.

……

"Mr. Ashford."

Just as Lucien was packing his things to leave, a tall wizard in a velvet robe was smiling at him through his crescent-shaped glasses.

"Principal." Lucien nodded politely.

"I heard from Professor Flitwick about your brilliant performance," Dumbledore said casually. "'The desire to let the feathers follow the airflow'—a very poetic way of putting it. But I'd like to talk to you about something else."

Dumbledore waved his wand, and the surrounding air became viscous.

It is a silent, ear-blocked incantation.

"The soul is a mystery, and your body doesn't need such wicked magic to sustain it, Lucien," Dumbledore said softly. "Especially when you try to dismantle it, it's dangerous."

"But how will we know what it is if we don't dissect it?" Lucien countered. "Like the Philosopher's Stone... if it were truly so perfect, why would Nicolas Flamel have kept it hidden?"

Dumbledore was taken aback.

"Don't be nervous, Principal," Lucien smiled. "I'm not that eager for immortality. Unlimited division at the cellular level will eventually lead to the wear and tear on the soul. This kind of low-level immortality is better left unfulfilled."

Dumbledore wiped his glasses.

This was the first time he had heard someone describe the Philosopher's Stone as lowly.

"It seems that Ravenclaw has indeed gained a remarkable student."

He lifted the soundproof spell.

"If you are interested in certain profound knowledge..." Dumbledore pulled a note from his robes, "this is a little privilege I'm giving you. But I hope you'll remember to turn on the light, even in the dark."

Lucian took the note.

That was a permit for a restricted book zone.

"Thank you, Headmaster." Lucien carefully put the note away. "I'll remember it. After all, only by understanding the structure of darkness can we better create light."

Dumbledore watched the boy's departing figure, stroking his beard thoughtfully.

“Not Tom…” he murmured, “more like… another Grindelwald? No, purer and colder than Gellert.”

Lucian walked out of the library, gently twirling the privilege slip in his pocket.

Only by learning how to build a bomb can you know how to defuse it perfectly.

This is the logic of a craftsman.