The crab laid thousands of eggs that hatched over the course of the next two weeks. Rhizen watched the hatchlings, sensing a tiny core in the bodies of each that contained a trace amount of Nacre.
There didn't seem to be any other changes to their bodies. They were somewhat stronger and healthier as compared to before, but the difference wasn't obvious.
'So, this is the type of change Yulna had been seeking.' He understood now. Unlike in the Aberrant World, her goal wasn't to turn the aquatic creatures into monsters.
Instead, Yulna only planned so that the aquatic animals would form a core that contained corruption. This would imply that the entire aquatic food chain would now revolve around corruption as the larger fishes would eat the smaller fishes and gain or strengthen their core.
Eventually, the entire marine region would be under the effects of the corruption. This was to make the world's essence gradually assimilate into it further, resulting in corruption becoming the core power of this world.
It was a sort of soft takeover. As Yulna didn't have enough power to directly swallow the world like Apocalypse, she hoped to first gain the world's acknowledgement before gradually taking control of the world.
As long as the world recognises the corruption as its inherent energy form, it would mean that Rhizen had lost, for Nacre would be resisted by the world following that.
'But now, I've taken advantage of this.' He smiled, watching the hatchling crabs eat up the powder that he had piled nearby. As they grow, their cores too would follow suit.
As the hatchlings continued to roam in the vicinity of their mother, a few feathers flashed past, picking up one per each.
Rhizen walked a short distance away, staring at a dog that he had captured, placing the hatchling crabs before it.
The dog had been starving for half a day already and hence, pounced upon the hatchling crabs, even if they were too small to even satiate its hunger. It quickly ate them all when Rhizen knocked it unconscious, touching its neck to see minor changes in its pulse.
Best
Slowly, as a few hours spanned past, a tiny core formed in its stomach, only spanning the width of a hair. It was almost impossible to detect even for him. But now that it had appeared, he smiled, waking up the dog as he fed it normal food.
Even though the efficiency was many times worse as compared to Horned Humans, a small fraction of the digested food was turned into Nacre, causing the core to grow ever so minutely.
"Good," Rhizen patted the dog, shooing it away as he returned to the breeding spot where the crab had begun to lay another batch of eggs.
He piled up enough Nacre-rich power for the crab to eat, hoping for it to lay as many eggs as possible in the one to two years of its egg-laying stage.
Just in case Yulna interfered, he erected Static Force defences all over the region before turning into a whale to plunge into the sea.
He then captured fishes from a variety of species that had just completed their mating stage and were about to enter their egg-laying stage, feeding them a few hatchling crabs each.
Upon seeing each of them develop a core, he fed them as much Nacre-rich food as possible, watching their cores develop gradually as they accumulated energy to begin the creation of eggs.
Weeks passed in such a fashion before the respective fishes began to lay down eggs, all of which contained a trace of Nacre now.
And once they hatched, the newborn fishes had the Nacre Cores, even though they were only hair-thick in size.
But as long as they grew, their core would develop in response. Moreover, if one of them lived long enough to lay down eggs in the future, all the newborns too would be born with a Nacre Core.
As a Whale, Rhizen watched some of these newborns be consumed by other fishes that developed a Nacre Core.
Upon seeing how easily the Nacre Cores formed in them too, Rhizen failed to conceal his surprise, "You've outdone yourself this time, Yulna."
As long as a creature consumed an animal with a Nacre Core, they too would develop a Nacre Core. This implied that within the span of a few years, the entire waters would be filled with fish that possess a Nacre Core.
'Wait, does this apply to humans too?' He wondered, waiting a week for some fishes to grow slightly larger before taking them with him as he arrived at a random city, chancing upon a hungry beggar to whom he fed them.
The beggar ate the fish with relish, even though they weren't enough to satiate his hunger.
'This is…' Rhizen felt his heart race as he noticed a Nacre Core appear in the beggar's stomach. This showed that a Nacre Core would form in the bodies of any living being that consumed a creature's Nacre Core.
Wondering what might happen, he fed the beggar a Beast Fruit, watching him become a Horned Human. As for the Nacre Core, it was absorbed into his Origin Space, reinforcing it a little.
'I see, this is good then.' He sighed in relief, watching the beggar prostrate before him. Rhizen simply uttered some words of consolation, motioning for the beggar to live a better life and help others needy like him.
Following that, he arrived at another kingdom, feeding a Nacre Core to a Horned Human, observing that the Nacre Core was dissolved and absorbed by his Origin Space, causing a mild increase in its Nacre reserves, not to mention a minor growth of the Mutated Beast living within.
'This solves one of the major defects of this power system.' Rhizen nodded. The defect was the over-dependency of the Horned Humans on the Mystic Humans, especially on the Nacre produced by the Tower of Purification.
That was the case in the other three worlds under PADS. But this world was different as they were more self-sufficient thanks to these Nacre Cores that would become widespread in the future.
It would also cause the Horned Humans to grow stronger, as unlike simply replenishing their Nacre reserves, the Nacre Cores also developed the Horned Humans.
Rhizen swallowed a Nacre Core, sensing that even though insignificant, his strength grew. It immediately placed the value of this world at the top of the list as Rhizen ensured to protect it to the limit.
'With this world and its production of Nacre Cores, PADS would be able to grow stronger faster.' He thought, smiling in the end as he returned to the sea, swimming through the waters to protect the growth of the fishes, ensuring as many of them reached maturity as possible so that they would mate and enter the egg-laying stage.
Once there was enough of a population of creatures with Nacre Cores, the food chain would take care of the rest. And what best way than to target the fishes that laid thousands of millions of eggs upon a single seating?
In the span of two months, the number of fishes with a Nacre Core exploded exponentially, now having enough numbers to warrant an automatic expansion.
Rhizen didn't just stop there. After all, it would still take time before the rest of the waters became the same. The world was just that vast. Hence…
Boom!
A massive container resembling a hill emerged out of the water, containing millions of fishes swimming within it.
Thousands of feathers were lodged along the sides of the container, carrying it as it flew at rapid speeds, moving towards a region two thousand kilometres away before dumping all the contents.
These fishes were in foreign waters now, immediately ganged upon by the natives there. And with that, a good fraction of the fishes in this region developed a Nacre Core.
Rhizen repeated the process, dumping millions of fishes with a Nacre Core into foreign waters, causing the aquatic population with Nacre Cores to boom from various locations. At this rate, within a year, there would be a fish with a Nacre Core in every region of the vast aquatic world.
Of course, Yulna wasn't twiddling her thumb while all this happened. She too released fishes with a Corruption Core into the ocean waters.
Though, she wasn't able to dominate like him as she had to first create another Devil Fruit, causing her plans to delay by two weeks. Moreover, she had to be subtle in her approach, unwilling to run into Rhizen.
So, she was slower than him. And hence, Yulna focused on the secluded lakes, seas, rivers, and the like, creating a region where fishes with Corruption Cores dominated the place.
There were plenty of locations where the seas had small mouths leading into the ocean. Such places were enclosed by landmass and served as the perfect locations.
After all, when the humans fished there and ate the Corruption Cores, the Blight Humans would grow while the Horned Humans would be poisoned by the same.
The case was similar to what would happen if Horned and Blight Humans consumed fishes with Nacre Cores. It was beneficial for Horned Humans and poison for Blight Humans.
As these two pinnacle entities waged a geopolitical war, the entire world was changing at an accelerated pace. Now, there existed one question.
Would the inhabitants be able to adapt fast enough?