The classroom was empty now. Slughorn sat alone behind the podium, holding Regulus's vial up to the light.
Pale red liquid rolled gently inside the glass.
"Perfect." There was real admiration in his voice. "In terms of magical purity and stability, this is even better than mine."
He set the vial down and looked at Regulus.
"What you did just now, guiding the ingredients' magic into fusing on its own, for a low-tier potion like the Wound-Cleaning Potion, it works." He paused. "You aren't the first person to do it, either."
Regulus met his eyes, calm as ever.
Of course Slughorn had seen through it. The man was a Potions Master, one of the best alive. If he hadn't noticed, that would have been the weird part.
And Regulus already knew the method had limits.
Once you got into higher-level potions, merging the magic inside the ingredients was only the start. Other things came into play too. Timing, method, sometimes the brewer's own magic had to be involved directly. Sometimes even emotion mattered.
That was the real advanced stuff. He knew a little about it, had heard fragments here and there, but he'd never seen it done with his own eyes. Knowledge like that didn't exactly sit around on open shelves.
None of that needed to be said out loud. He stood there quietly, a touch more respectful than usual, and waited for Slughorn to continue.
Slughorn's gaze drifted to the window, as if he were looking at some distant point in time instead of the grounds outside.
"Centuries ago, before potion-making had been standardized, some wizards brewed exactly the way you did. No fixed procedure. No official recipe. Just instinct and raw perception. They'd pick up a plant, smell it, feel it, and know what it should pair with, how it ought to be used. The results were often far better than what our neat little modern instructions can produce."
His eyes came back to Regulus. "Do you know why that approach disappeared? Why we ended up with the system we use now?"
Regulus thought for a moment. "Because it was too hard?"
Slughorn nodded at once. "Absurdly hard." He leaned forward a little. "Talent wasn't enough. Neither was hard work. You needed a kind of affinity with the materials, something close to instinct. You had to hear what their magic was saying. See what they wanted to become. Hold dozens of constantly shifting magical signatures in your head at once and respond within a thousandth of a second. One mistake, just one, and the ingredients were ruined."
He shook his head.
"There have only ever been a handful of wizards who could do it. Every Potions Master from that era was a legend. Our modern system made potion-making reproducible and teachable. A wizard with average talent can still brew something usable. A genius won't lose a fortune in materials because of one lapse in concentration. That's progress."
His expression turned serious.
"But you... you did it."
Regulus said nothing. He waited.
Slughorn was quiet for a beat before speaking again.
"Regulus, what do you think a potion is?"
Regulus parted his lips to answer, but Slughorn lifted a hand.
"Not yet. Let me answer first."
He got to his feet and walked to the window, hands behind his back.
"Most people think potion-making is just tossing ingredients into a cauldron in the proper order, waiting long enough, and calling it a day. That's wrong. A potion isn't a heap of ingredients. It isn't even just a chain of magical reactions."
"At its core, a potion is different kinds of magic learning to accept each other under specific conditions, until they become something entirely new. A complete magical whole. That whole has its own life, its own temperament, its own inclinations. A successful potion is less like a product and more like a newborn creature. It has personality. It has purpose."
He returned to the desk, picked up the Wound-Cleaning Potion, and turned it so the light passed through it.
"Take this, for example. The healing tendency inside it doesn't belong to any single ingredient. It was born from dittany, dragon blood, ashwinder eggshell, and daisy root together. Dittany on its own can only stop bleeding. Dragon blood by itself is unstable. But when they become a Wound-Cleaning Potion, they turn into something new. Something with the will to heal."
He put the vial down and looked straight at Regulus.
"What you did was sense the magic in those ingredients and guide them into accepting one another, into merging. But you were not making a Wound-Cleaning Potion. You were allowing those ingredients to become one. Those are completely different ideas."
Regulus stayed silent.
Slughorn went on, "If you can do that, then your perception and understanding of magic already surpasses most fully grown wizards. That's talent. It's also ability. But there is something I need to warn you about."
His face grew even more serious.
"Magic is alive. The magic in raw ingredients is alive. The magic in a finished potion is alive. When you guide those forces into fusion, you are dealing with living things. They have inclinations of their own, and yes, you can shape them. But that process changes you too."
He held Regulus's gaze.
"Do it for long enough and you will get used to bending magic to your will. That is not automatically wrong. But remember this, magic is not a servant. It is a partner. You may guide it. You may work with it. But if you try to enslave it..." He let the words hang for a moment. "One day, it will push back."
Something in Regulus's chest shifted.
That warning echoed what the entity in the Slumbering Abyss had shown him. Invitation, not control. Resonance instead of domination. Faint, but unmistakable.
He nodded, and this time there was no trace of perfunctory politeness in it.
"I understand, Professor. Thank you."
Slughorn studied him for a long moment, then smiled. He looked satisfied. A little wistful, too.
"Good. As long as you understand." He sat back down, the gravity draining from his posture. "Off you go. From now on, brew however you like in my class. Just don't show off too much. The other students will lose heart."
"I'll remember that, Professor. What you've told me means a great deal."
Regulus gave a slight bow, said his goodbye, and left.
Outside the Potions classroom, Cuthbert and the others were still waiting.
Regulus gave them a small nod and kept walking. They fell in behind him without a word.
Cuthbert and Alex didn't think much of it. Regulus getting stopped after class by a professor was basically routine now. They traded a look, shrugged, and moved on.
Hermes walked half a step behind, studying Regulus from the corner of his eye.
He kept thinking back to what he'd seen in class. Whatever Slughorn had wanted to say, it had to be connected to that. But Regulus hadn't offered an explanation, so Hermes acted like nothing had happened.
His thoughts drifted to his own summer.
Two months in the family training chamber, almost every waking hour. His father had personally taken over his training, sparring with him, teaching him the truly dangerous things.
Modified applications of Dark Magic. Switching spells mid-combat. Concealing killing intent while casting.
One day, his father had taken him somewhere, and that trip had shown him what real power actually looked like.
He had thought he'd made huge progress. In strength. In perspective. In all of it.
And then class had happened.
He handed over the ingredients, poured, and finished.
Like some invisible master had stepped in and done a whole round of work nobody else could even see, and the potion had simply made itself.
The gap between him and Regulus hadn't narrowed at all.
It had gotten wider.
Because he couldn't even begin to understand what he'd just witnessed.
He looked away and kept walking.
Regulus, meanwhile, was turning Slughorn's words over in his head.
Stripped down to the basics, the message was simple.
Don't fight magic. Treat it like a partner. Magic is alive.
It sounded almost like philosophy, the sort of thing an old wizard might mutter over tea.
Be friends with your magic. Listen to it. Learn what it wants.
That kind of thing.
But then he remembered the headmaster's office. Dumbledore had said something similar.
Converse with magic.
Dumbledore and Slughorn were unquestionably the greatest in their respective fields.
Dumbledore was recognized as the greatest wizard of the century. Slughorn did not have that same mythic reputation, but in potion-making, he was an authority without equal.
And their views on magic, on its nature, were startlingly alike.
So Regulus turned the question inward.
What was his current relationship with magic?
Not hostile. Not conversational.
Transactional.
He used magic the way a person used a tool. If he needed an effect, he used magic to produce it. It was an extension of his will, almost an extension of his body. Obedient, efficient and reliable.
And that was all.
But both Dumbledore and Slughorn had made it clear that wasn't enough. It required communication, accommodation, and partnership.
He knew they weren't wrong.
But was that the only correct path?
His mind went to Voldemort's Dark Awakening.
That pointed in the exact opposite direction.
It was domination, control, the absolute subjugation of magic. No communication, no yielding, no partnership, only mastery.
And Voldemort had climbed to the summit that way too.
Regulus let the question rest.
He pulled himself back to the present.
They had already reached the dormitory.
He pushed open the door and walked inside, the others following after him.
Cuthbert sidled over at once, curiosity all but written on his face.
"Regulus, what did the professor say? You've been thinking the whole way back."
Alex glanced over as well. Hermes sat on the edge of his bed, watching.
Regulus looked at the three of them.
There was a brief silence.
Then he shook his head. When he spoke, there was something quiet in his voice, something firm.
"Slughorn is a good professor."