The end result of Potions class wasn't a mystery.
When Professor Horace Slughorn called time and told everyone to bottle their work for inspection, Regulus Black's vial looked like it belonged on an entirely different table.
Around it, other bottles were… questionable. Some were the wrong color. Some were cloudy with bits still floating inside. A few burbled with suspicious little bubbles, like they couldn't decide whether they were done brewing or about to explode.
Only Regulus's potion sat perfectly clear, a pale green that caught the light like something clean and alive. When the liquid settled, there wasn't even a hint of sediment.
Slughorn picked it up and held it to the torchlight for a long moment, his round face openly delighted.
"Exemplary!" he announced, voice booming off the dungeon walls. "Mr. Black, this is well past acceptable, it's excellent. Tell me, did you use some special technique?"
"I just treated the ingredients properly, Professor," Regulus said, calm as ever.
He didn't sound like he was showing off. He sounded like he was reciting facts.
"Snake fang powder needs to dissolve completely. The tip of the porcupine quill carries the strongest concentration of magic. And the fluxweed's balancing effect has to be timed precisely."
Slughorn's eyes brightened. "You mentioned where the magic is most concentrated. Is that something you observed yourself?"
"Yes, Professor," Regulus said. "By sensing the faint magic the materials give off."
Whispers flickered through the room.
Sensing an ingredient's magic?
Was that something a first-year was even supposed to be able to do?
Slughorn didn't push. He just gave Regulus an approving look and nodded once. "Come to my office after class, Mr. Black."
Afterward, Regulus spent ten minutes in Slughorn's office.
The professor was warm and expansive, showing off shelves of rare ingredients with the pride of a collector. He hinted, not very subtly, at the existence of the Slug Club. Then, as if it were the most natural thing in the world, he handed Regulus a small vial of Felix Felicis as encouragement.
It was diluted, but even so, for a first-year it was an unbelievable gift.
"Keep that talent sharp, my boy," Slughorn said, patting his shoulder. "Potions isn't only nimble hands, it's sensitivity. You've got that."
Regulus thanked him and slipped the diluted Felix Felicis into the inside pocket of his robes as he left.
Used well, it could save your life.
Used badly, it could create problems you'd regret.
Transfiguration was held on the second floor in a bright classroom with wide windows. Sunlight spilled across the desks, and the air smelled faintly of wood and parchment.
Professor McGonagall was already waiting at the front. She wore a dark green robe, her hair pulled into a severe bun, her expression as sharp as her posture.
"Transfiguration," she began once everyone was seated, "is among the most complex, most dangerous, and most elegant branches of magic.
It requires precise incantation, clear intent, and an understanding of matter itself."
She lifted her wand and tapped the desk lightly. A matchstick became a silver needle.
"Today, we start with the basics," she said. "Match to needle."
Matchsticks were passed out. Students began to try.
The room quickly filled with mumbled spells and frantic wand movements. Most of the matchsticks only twisted and warped, turning into awkward little things that were neither match nor needle.
Regulus picked up his matchstick and studied it.
Stable structure. Wood fibers arranged in a predictable pattern. A sulfur tip with its own composition. Shape, density, balance.
Transfiguration didn't create something from nothing. It changed what was already there.
Rearrange wood into a metallic crystal structure. Convert the sulfur into a silver point. Keep the object continuous, whole, instead of tearing it apart and pretending it was fine.
He raised his wand and spoke softly.
He barely tapped the matchstick.
It shivered once on the tabletop, then the change began, gradual and smooth. The brown wood lightened into silver-white as the grain vanished and the surface turned sleek. The sulfur head shrank, reshaped, sharpened.
Three seconds.
When it was done, a perfect silver needle lay on the desk, straight as a drawn line, the eye cleanly formed.
McGonagall happened to reach his table on her circuit.
She stopped, looked down, then picked the needle up and held it to the light.
"Perfect transfiguration," she said, and there was a trace of surprise in her voice. "One attempt. No repeated corrections. No residue. Mr. Black, have you practiced this spell before?"
"I've practiced the principles, Professor," Regulus replied. "But this is my first time using it on a matchstick."
"The principles?"
"The stability of material structure," Regulus said, taking the opening without hesitation. "And conversion efficiency."
He paused, then added, "Professor, may I ask a question?"
McGonagall's brow lifted slightly. "Go on."
"What are we actually changing?" Regulus held up the needle. "We turn a matchstick into a needle, but in the process, what changes?
Is it the object's essential nature, or only its outward form? If it's the first, is the match truly a needle now? If it's the second, how is it different from an illusion?"
The classroom went quiet. Even a few students still wrestling with their matchsticks looked up.
McGonagall's focus sharpened. She studied him for a few seconds, then said slowly, "That is not a question most first-years think to ask, Mr. Black."
"I still want the answer," Regulus said.
McGonagall set the needle down and moved to the front, turning to face the class.
"Mr. Black has asked something important," she said. "The core difference between Transfiguration and illusion is material continuity.
An illusion creates an image without substance. Transfiguration guides existing matter to reorganize along a magical path."
She picked up another matchstick and tapped it. It became a feather.
"This feather," she said, holding it up, "was a matchstick. The material foundation did not vanish. It was rearranged. That is why true Transfiguration requires an understanding of what you are changing.
You must know how wood becomes feather structure, and you must guide that conversion, not simply alter appearances."
Her gaze returned to Regulus. "Does that satisfy you?"
"Partly, Professor," Regulus said, inclining his head from his seat. "But it leads to another question. If Transfiguration is matter reorganized, then what about the Vanishing Spell?
It makes an object disappear entirely. Where does the matter go? Or is Vanishing an extreme form of Transfiguration, turning something into nothing?"
This time, even McGonagall went still.
The room held its breath. Students stared at her, not even sure what the question meant, only aware that it was the kind of thing you didn't usually ask a teacher on the first week.
McGonagall drew in a measured breath. "The Vanishing Spell is N.E.W.T.-level material," she said at last, each word precise. "It involves the conversion of matter and energy, as well as theoretical magic across dimensional boundaries."
Her eyes didn't leave him. "Focus on the task in front of you, Mr. Black. Your match-to-needle is excellent. Five points to Slytherin."
She turned back to the rest of the room and resumed her instruction.
For the remainder of the lesson, Regulus could feel her gaze touch down on him now and then, brief and assessing.
Regulus stayed quiet.
He already knew the answer to his own question.
What interested him more was the difference in McGonagall's response compared to Slughorn's.
One encouraged.
One watched.
It was a kind of line being drawn.
A choice of sides.
When Transfiguration ended, Regulus had only just stepped out into the corridor when someone blocked his path.
Narcissa stood near the corner, her long blond hair catching the sunlight until it almost seemed to glow.
As a seventh-year, she carried herself with a practiced elegance. Her dark green school robes were pressed perfectly flat, and the silver Slytherin badge at her collar shone like it had been polished that morning.
"Regulus."
"Cousin Narcissa."
"Come with me," she said. "We need to talk."
She turned into a quieter side passage. Regulus followed.
Narcissa stopped and faced him.
"I heard about last night in the common room," she said bluntly. "You humiliated a Travers boy in front of everyone."
"He asked for it."
"I know," Narcissa said, and there was a hint of approval under the sharpness. "He is an idiot. His father's Ministry position came through marriage connections, not ability. That isn't the point."
She stepped closer, lowering her voice. "The point is that you showed too much, Regulus.
First day. First night. In front of all of Slytherin. Do you understand what that means?"
Regulus met her eyes, steady. "It means I'm not easy to push around."
"It means you're on certain people's radar," Narcissa corrected. "Earlier than you expected."
She glanced around once, making sure they were alone, then continued, quieter still. "At breakfast, Rabastan Lestrange asked about you. You know him, Rodolphus's brother.
He had questions. What training you've had. How strong your magic is. What you think about certain things."
"What things?" Regulus asked.
Narcissa's stare hardened. "You know what things."
Then she said it, crisp as a verdict. "He's paying attention to talented young wizards. Especially pure-bloods.
Your brother's betrayal dragged the Black family down in his eyes. But now you've appeared, younger, more gifted, and you look like you fit what he wants from a Black."