In every world Percy had been to, potions were considered secondary products of alchemy – far inferior to the cultivation resources people used to cleanse their cores and advance to the higher grades. Part of it was due to the sheer importance of elixirs. After all, very few things could compete with a permanent increase to one’s power or lifespan.

But it didn’t help that potions were inherently flawed either.

Typically brewed out of Orange plants, their efficacy was barely worth mentioning when consumed by those at the higher grades. Percy had experienced first-hand how his most recent advancement had muted his potions’ effects on his own body, and Yellow wasn’t considered a high grade either. For people like Galahad or Archibald, potions were completely useless – let alone gods and demigods.

The reason for that was fairly simple too.

Every living creature required a mana core to survive, and that included plants – which potions were made of. That said, the way in which mana cores manifested was very different for flora than it was for fauna.

When it came to animals, Brown was a grade reserved for only the tiniest of creatures – such as insects. Any mundane animal larger than that – from mice to whales – usually had a Red core instead. Once a beast reached Orange, both its body and its demeanour changed in all sorts of ways, and it was almost always considered a magical creature.

Of course, there were some exceptions. The Starry Wasps Percy had hunted before were insects, so they turned into magical creatures as early as Red – in the form of the Starry Drones he had seen at the base of the Fungal Spire.

Plants, on the other hand, didn’t have a single mana core. Instead, they possessed a vast network of minuscule nodes, spread evenly along their volume. Mundane plants had a Brown core regardless of their size. Even a towering tree could have that, though its mana would barely be perceptible in that case, due to how thin it was, and how widely it was distributed.

Meanwhile, magical plants were mostly found at Red or Orange. The former were used as secondary ingredients for various alchemic steps, their properties often determined by their affinity, while the latter were considered main ingredients out of which potions could be brewed.

As a result, potions were essentially always at Orange, regardless of the grade or the skill of the alchemist who had brewed them, or the method that they had employed. Yellow plants did exist, but they were far rarer than Yellow-born sapients or beasts, and a slightly more potent potion wouldn’t exactly be enough to fix the problem either.

Sadly, plants never had the beast affinity nor any intelligence, so it was impossible for them to advance, and thus the whole universe was stuck without Blue or Violet potions – generally speaking.

There were some unique plants that seemed to break all convention, like the jade tree the Divine Order had gifted to House Avalon, which was brimming with dense life mana, or the Lotus of a Myriad Rivers Percy had used to change Micky’s affinity.

Percy hadn’t the slightest clue how such things could even exist, nor did he know whether anybody had ever succeeded at brewing anything with them, but they were clearly rare enough that it would be a waste to use them for a one-time consumable product with a temporary effect.

However, it appeared there was another, more reliable way to concoct potent potions – one which the Amenthei had discovered.

The compression principle.

Rather than relying on the occasional higher-grade plant, these people had instead come up with a method of fusing many regular potions into a more potent variant! The idea was simple enough that every alchemist had considered it at some point – Percy included – though this was his first time coming across a civilization that had managed to realize it.

Sadly, their approach had its own share of drawbacks.

In theory, one would need a minimum of three Orange healing potions to brew a single Yellow potion, three Yellows for one Green, and so on. In practice, there would inevitably be some losses – much like with every other alchemic step Percy had studied in the past. These losses were comparable to the losses incurred when a Yellow creature consumed an Orange potion, which kinda defeated the purpose of the technique.

Simply put, a similar quantity of Orange ingredients would be wasted to heal a Green's injury, regardless of whether those losses were incurred inside a cauldron during the brewing process, or inside that person’s body.

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‘No. That’s only the case for the average alchemist… If your brewing yield is high enough, you can probably get more value out of your ingredients this way…’

Percy’s yield was already extremely high for both his age and his grade, thanks to his constant cheating. If he were to master another alchemic principle, it would likely climb again, so this would probably be worth it for him. And this would get even better once he stumbled upon more principles in the future, or once he upgraded his Alchemist’s Intuition to Refined.

If he could get his brewing yield close to 100% – or at least 90% – one day, he might be able to brew something like a Violet healing potion with just over a hundred of his green mushrooms. Meanwhile, if a Violet mage wanted to receive the same amount of healing from the regular potions, they’d have to consume closer to a thousand mushrooms’ worth.

Furthermore, it wasn’t just the wasted ingredients that one had to consider.

There was also a question of practicality. A single Violet potion was something one could easily swallow in an instant, whereas taking a thousand Orange potions meant drinking a whole bucket. And if Percy wanted to use his potions in tattoo form… Well, there simply wouldn’t be enough space to draw them once he reached Blue or Violet, even if he covered every inch of his body with Orange ink.

Thus, learning and incorporating the compression principle into his brews was the only way for Percy to not waste all the time and effort he’d previously spent with his other principles.

Thinking of something else, he couldn’t help but raise an eyebrow.

‘It actually goes so much further than potions… Understanding how to forcefully elevate the grade of a potion might help me come up with a way to advance without elixirs… Or to at least make elixirs more useful…’

Percy didn’t think the compression principle could be applied to elixirs directly, because nectar worked differently from other ingredients. Much like his crystallized mana, it wasn’t separated into different grades. Starry Soldiers and Knights simply produced more of the same substance than Drones or Workers, rather than a more potent form of it.

That said, he already had some ideas that he wanted to test in the future.

His boosting art already almost raised his grade – though it was missing a couple of steps. On top of that, Percy wanted to try drawing runes inside his core at some point, using pre-casting. Adding the compression principle into the mix, and he might just have enough tools in his arsenal to induce an artificial advancement.

It was an ambitious plan, but it was also exactly the kind of thing he’d need to invent if he ever hoped to attain divinity as a Red-born. His next advancement was over a century away, so he’d probably have to give this a shot before that once he had the time for it.

‘Alright. I’m sold, but that still doesn’t solve my immediate problems...’

As much as he wanted to study the new principle, he didn’t have the time to read everything here in detail. Percy would have to skim through the information on the ceiling to understand the gist of what the Amenthei had done. As for actually practicing and registering the technique, he’d have to wait until he returned to Remior – assuming he found a way out of the Sanctuary.

‘Let’s not dilly-dally, then…’

Not wasting another second, Percy downright skipped all the historical information about how the first alchemists on Amenthes had originally discovered the principle, and all their failed experiments from back when the technique was still in its infancy. Practically running through the hall, he scanned the relevant sections both above and below, searching for the fundamental components necessary to study the principle by himself.

‘…much like a core’s promotion, elevating a potion’s grade comes down to compressing the mana down into a denser state – hence the name of the principle…’

‘Yeah, no shit… I could have guessed that by myself!’

Rolling his eyes, he moved on to the next paragraph, and the one after, ignoring all the details he didn’t think were crucial.

‘…but simply compressing the liquid from the outside isn’t enough. A mage passively uses their willpower to condense the mana inside their core. Sadly, it’s impossible for us alchemists to infuse our willpower into an ingredient’s mana, so we had no choice but to look for an alternative…’

Percy yawned for the millionth time since coming here – the tenth this very minute, in fact. Realizing he was running out of time, he hastened his steps, knowing he was close to the answer.

‘…the most important thing is to use a secondary ingredient rich in gravity mana. It pulls at the potion from within, helping greatly with the compression…’

‘There! Now we’re getting somewhere!’

‘…but that alone isn’t enough. External pressure is needed as well, and the two sources have to be applied in a very specific manner. One must press down on the liquid rhythmically, catalysing the gravity mana within the secondary ingredient. Each potion requires a different compression amplitude and frequency, which can only be discovered through trial and effort…’

Percy would have loved to continue, but keeping his eyes open was already a monumental task, and he still had a whole pyramid to traverse.

‘Anyway, this should be enough… A secondary ingredient rich in gravity mana… varying the external pressure to find the right frequency… Shouldn’t be too hard…’

Shrugging, he sprinted toward the exit in the opposite side of the room from where he’d entered. Next, he climbed a few stairs to another hall right above the previous one. It looked more or less the same too, though it was slightly smaller, likely because it was higher up in the pyramid.

More importantly, it was also set up like a library, though its contents seemed quite different from earlier…