Chapter 41: Stacking Passives
Regulus Black had arrived at a rather dangerous idea.
A fatal strike aimed at all carbon based life, one that even wizards would not be exempt from.
What compound was lethal to almost every carbon based organism, and could, at least in theory, be produced on the spot through Transfiguration?
Cyanide.
Whether as hydrogen cyanide gas or as cyanide ions, it was viciously efficient. A tiny lethal dose, onset measured in moments, and a ruthless ability to choke off cellular respiration before the victim even understood what was happening.
The air held nitrogen and carbon. Water vapour supplied hydrogen.
If a wizard's control over magic were truly absurd, if it reached a level that bordered on the impossible, then in principle they could isolate those elements from the surrounding environment and force them into hydrogen cyanide, delivering it straight into a target's lungs.
It was not merely molecular rearrangement. It would demand something closer to atomic level manipulation, along with element identification and synthesis control performed in real time. For now, it was fantasy, a thought experiment and nothing more.
Still, the wizarding world was never short of miracles. Impossible things had a nasty habit of becoming possible when someone talented enough refused to accept the ceiling.
At the very least, the idea pointed towards the heights Transfiguration might reach in extreme circumstances. It would stop being a helpful combat tool and become the most secretive, lethal weapon imaginable.
If struck, a truly skilled wizard might manage some kind of desperate self rescue. A slower one would simply die.
Regulus tucked that line of thought away. It was far away. Perhaps unattainable forever.
But it was a direction.
Hermes Mulciber finally hauled himself up from the floor, bracing a shoulder against the bedpost. He kept his head down and did not dare meet Regulus Black's eyes again.
The arrogance that had once filled him had been smashed into pieces. What remained was wariness and fear, and a thin, twisted strand of curiosity about that power he had never even noticed as he chased darker things.
The confidence he had entertained, the idea that he could turn the tables later with family Dark Arts, felt laughable now.
He needed to reassess everything, including himself, and how he was meant to live with this terrifying roommate.
Quiet returned to the dormitory.
A faint smile touched the corner of Regulus's mouth as he picked up a fresh piece of graphite and began another round of practice.
Transfiguration that reached into the essence of matter was fascinating, but he knew the truth of it. It demanded years of accumulation. It would not be conquered in a week.
Right now, he needed something more immediate. Something that mattered more than brilliance in a classroom.
He needed defence.
The threat drawing closer to Hogwarts was not a school rivalry or a fellow first year with an attitude problem. It was Lord Voldemort.
Occlumency came first.
The original account was clear. Severus Snape survived as a spy because he could stand before a master of Legilimency and not be peeled open like fruit. Occlumency was not only protection against mind reading. At its highest levels, it could even help resist control, perhaps even the Imperius Curse.
If Regulus intended to move in shadowed circles and live, it was essential.
But Occlumency alone was not enough.
He began thinking in terms of passive magic, spells and workings that could remain active without constant attention, or trigger on their own to protect a wizard. Hogwarts did not teach such things in the normal curriculum. They were treated as advanced, obscure arts, scattered through the private libraries of ancient families and buried in specialist texts.
Occlumency was the core of all mental passives, the foundation stone.
For Regulus, the Restricted Section was no longer a forbidden place he had visited once. It was either visited zero times, or visited countless times.
On a Wednesday night before Halloween, with the castle unusually still, he decided to slip in again.
The route was familiar. The timing was easy. The improved Disillusionment Charm blurred him into stone and shadow, and the corridors yielded to him as if the castle itself had decided to look away.
He did not linger. This was not curiosity. It was purpose.
With his scanning style of reading, he moved quickly through the relevant shelves and committed the core information to memory.
Several titles caught and held his attention.
"Fortress of the Mind: Essentials of the Art of Mental Defense."
"Ancient Protective Rituals and Eternal Magical Inscriptions."
"The Essence of Magic: On the Shaping and Disguise of Personal Magic."
"An Introduction to Dark Arts Detection and Countermeasures."
"Soul Resilience: On Resisting Subjugation and Beguilement."
"The Hidden Path: Tracking, Counter Tracking, and Magical Mists."
Hogwarts's collection was unfathomable. Even this narrow selection hinted at a field of study vast enough to swallow years.
Back in the dormitory, Regulus began practising Occlumency at once.
The books were consistent. The core of Occlumency was control, strict control of thought and emotion leakage, paired with construction. A mental structure deep within the mind, either solid as a fortress or deceptive as a maze, built to confuse and mislead anyone who tried to intrude.
Training was described in layers.
First came the basic barrier. A simple wall at the edge of consciousness to keep surface thoughts from wandering freely and being plucked at will.
Second came organisation and partition. Memories, knowledge, emotions, all sorted into separate rooms, with deliberate boundaries.
Then came deception. False thoughts or half memories, believable enough to look natural, pushed forward as bait when pressure was felt.
Finally came deep solidification and automatic defence. The barrier and the decoys trained into instinct, so that even without conscious effort, the subconscious maintained the basics. The deepest core remained locked away behind complex, shifting access paths.
For Regulus, starting was almost seamless.
His mind was already unusually stable. Star Path Meditation had tempered his soul again and again, turning focus into habit rather than effort. He built the basic barrier quickly. Partitioning came naturally to him, tidy and methodical.
Even so, he understood the gap between competence and mastery. To deceive someone like Lord Voldemort, a true Legilimency master, would require far more time, far more refinement, and the hardening that only pressure could provide.
Still, the door was open. The rest was time and adaptation.
A thought surfaced as he worked.
What if he used the dynamic model from Star Path Meditation as the core of his labyrinth?
Hide the most important secrets inside a constantly running astral structure, vast, shifting, and computationally complex. Even if an intruder broke through the outer walls, they would face a star filled sky with no borders and no still points. Understanding it would take immense effort. Finding anything useful inside it might be impossible.
Over the next two days, he consolidated Occlumency and began experimenting with other passive defences.
He worked on what the texts described as a constant shield, shaping his own magic into an extremely thin, evenly distributed protective layer along the skin. It demanded continuous adjustment at the edge of perception. It was exhausting, and he could only keep it stable for a short time.
He also trained his sense of danger, combining it with his sharp magical perception. He forced himself to notice the faintest malice in the environment, the subtle shift in intent that preceded action.
Passive magic was not easy to learn.
It did not offer explosive power. It demanded subtle control of mind and magic, slow transformation built through repetition.
But the value was obvious.
Once established, these workings integrated into instinct. Armour you wore without thinking. A radar that ran without rest.
They warned before danger arrived.
They softened the first blow if an attack slipped through.
They protected the deepest secrets when someone tried to pry.
For someone who intended to manoeuvre near the dark faction and survive, these skills mattered as much as any killing curse.
Friday afternoon, Potions ended early.
Regulus headed towards the library as usual, but in a secluded corridor connecting the dungeons to the main staircase, he heard shouting and jeering that carried a familiar rhythm.
Loud laughter.
A voice that cut like a sneer.
He turned a corner and saw them.
James Potter. Sirius Black. Peter Pettigrew. Remus Lupin, hovering near the edge as if he wanted to stop it, yet doing little to stop it.
They had Severus Snape surrounded.
Snape's robes were splashed with some slimy potion residue that gave off a foul, unnatural stench. His hair was soaked and clung to his face. His expression was so dark it looked painted on.
His wand was clenched in his hand, but with James and Sirius on either side of him, he looked boxed in and alone.
James's grin was wide.
"Look who it is," he crowed. "Dear Snivellus doing his little potion experiments again. Planning a new stink attack this time?"
"Let me go, Potter," Snape rasped. The words sounded scraped through his teeth.
"Let go?" James laughed again. "We're only helping you clean that unidentified object off your robes. It's filthy, just like you."
Sirius lounged against the wall, casual as if this were sport. His smile was bright with rebellious delight.
Regulus stopped.
He did not step forward.
He simply watched, quiet as a shadow, and let the scene unfold.