What Regulus wanted wasn't merely to copy the Mandrake's properties. He wanted to understand them. Then surpass them.
And he didn't want the Mandrake's decomposition alone. He wanted decomposition itself.
Weathering and erosion in the physical world: rock slowly stripped away by wind and rain, whole slabs becoming gravel, gravel becoming sand.
That was decomposition.
Structural collapse at the level of enchantment: a precise magical circuit severed by external force, the spell failing, the magical construct reverting to raw materials.
Also decomposition.
The breakdown of living tissue: cells losing function, organs ceasing to cooperate, a whole that once ran and leapt and thought becoming a corpse.
Still decomposition.
The undermining of a magical artifact's very foundation: the magical imprint bonded to an object erased, a family heirloom passed down for a thousand years returning to ordinary metal and wood.
Decomposition all the same.
What he needed was a universal logic of decomposition, one that could address every category of target.
The Mandrake's version fell far short. He needed decomposition in its purest form.
Regulus lifted his head.
Outside the window, full dark had settled. The sea and the night sky merged at the horizon, water indistinguishable from air.
A handful of stars punctured the cloud cover, burning at enormous height. Silent and eternal.
He thought of Betelgeuse. The red supergiant, seven hundred million times the volume of the Sun, six hundred and forty light-years from Earth.
Light traveling at three hundred thousand kilometers per second for six hundred and forty years before it reached his eyes.
What he saw was a star as it had been six hundred and forty years ago.
Back then, the three belt stars of Orion had already shifted from where he saw them now. The change was too slow for human lifetimes to register, centuries too short to notice, but the drift was real.
Stars had lifespans too.
They burned hydrogen, burned carbon. Millions of years. Tens of millions and billions. Then the fuel ran out.
Low-mass stars swelled into red giants, shed their outer layers into space, and collapsed at the core into white dwarfs.
High-mass stars accumulated iron cores until they hit the critical threshold, could no longer resist their own gravity, imploded, rebounded, and detonated into supernovae.
At peak, the brightness exceeded an entire galaxy's combined output.
At peak, every heavy element forged through fusion was flung into the void.
Those elements drifted through darkness for millions of years, caught by gravity, condensing into new stars. New planets.
Earth's iron core came from a supernova that had detonated six billion years ago.
Every metal fitting on his body, mined from the planet's crust, contained iron atoms forged in that explosion, hurled outward, captured, and buried over the aeons into some vein of ore.
Even stars ended.
Order became chaos. Chaos was reorganized by gravity into new order.
Wasn't that decomposition?
Loosening what had already set. Freeing energy that had already solidified. Returning a thing to the state where it could become something else.
The Mandrake's magic was decomposition: seven and a half loops of magical circuit dyeing pure life-magic with a new property, stripping any whole it touched of the definition of wholeness.
A star's life cycle was also decomposition: gravitational collapse severing the binding energy between atomic nuclei, an iron core disintegrating in a thousandth of a second, six billion years of accumulated matter returned to the universe.
One was magic's path. The other, physics' law.
Six hundred and forty light-years apart. Six billion years apart. Separated by the boundary wizards and Muggles had each drawn around their respective domains.
But the underlying logic was the same. Order reverting to chaos. Chaos regaining the possibility of being redefined.
Outside the window, deep night. Sea wind pushing in from the east, carrying its coolness.
He wanted to replicate stellar collapse as a spell. That might lie beyond any wizard's reach entirely.
But he could bring that perspective in.
The Mandrake's decomposition made skin no longer skin, flesh no longer flesh, bone no longer bone.
Stellar decomposition made iron no longer iron, silicon no longer silicon, oxygen no longer oxygen.
The decomposition he wanted would return any existing thing to the state before it had been organized into existence.
Plants weren't the only things that could do it.
Physics could. Gravity could. Time could.
Whether magic could?
Regulus looked out at the sea.
Waves struck the rocks. Thousands of years, tens of thousands, countless days and nights without pause.
He had no answer. But he wanted to find out.
He filed the thought away.
The vision was too vast, something to pursue as an ultimate goal, built toward over time.
There was still an enormous amount to accumulate before he got there. For now, perfectly replicating the Mandrake's decomposition magic counted as a milestone.
But Verdant Magic, as a path, had been opened. Or rather, Regulus had cut his own trail through it.
His approach to developing Verdant Magic had diverged entirely from the ancestor Eldrin's direction.
As for what remained: if he ever wanted to acquire the properties of another magical plant, the method was the same road walked again.
Understand then replicate it and then transform it into something of his own.
And the Decomposition Curse itself... now that spell development was complete, he no longer needed the incantation. The wand could stay put away.
Among every spell in his arsenal, this one might be the most insidious.
Regulus sat by the greenhouse window, staring at his open palm.
Judged by its effects alone, this magic fell squarely within the Dark Arts.
Its direct function was killing. Reducing a living being from a whole to fragments, from existence to nonexistence.
If the Ministry of Magic's classification standards were strict enough, the Decomposition Curse belonged on the same page as the Killing Curse.
But it didn't require intense negative emotion to cast.
Not for him, at least.
When he cast it, his mind held nothing but the magic model. The logical structure of decomposition. No hatred, no killing intent, no dark emotion that needed summoning.
Everything was ready-made, like a product rolling off an assembly line. Fill in the parameters, and the result emerged on its own.
The Killing Curse demanded genuine murderous will. The pure, focused desire to see the target dead.
The Patronus Charm demanded the happiest memory. Positive emotion fed into that silver light until it blazed.
What did the Decomposition Curse demand?
Understanding.
A true comprehension of what it meant to make the whole no longer whole.
But unlike Space Warp, which could be taught by explaining the key principles, handing someone the incantation and the wand movement, and letting them learn...
The Decomposition Curse had an unavoidable threshold. The caster had to build that magic model inside their own mind.
Regulus considered. First, the other person would need to understand decomposition.
Making the whole no longer whole. Turning a unity into countless isolated fragments. Order reverting to its primitive state.
That kind of understanding resisted verbal transmission.
He could explain the Mandrake example, could demonstrate the effect, but whether the student grasped it would depend entirely on them.
Only with that understanding could they, while constructing the magic model, let the abstract concept of decomposition permeate every thread of magic within it.
This probably qualified as a high-tier spell by any standard.
Maybe Father could give it a try.