Chapter 4
‘Beautiful.’
As Nereia wandered around the hydrothermal vent, it couldn't take its eyes off the various deep-sea creatures.
Some deep-sea creatures escaped predators by absorbing and then emitting the faint light given off by rocks embedded here and there.
Others, apparently especially resistant to heat, had built nests around fissures spewing hot hydrothermal fluids and gas directly.
Various other creatures were scattered all around, and one of them caught Nereia's eye.
It was something resembling a small crustacean.
It looked similar to creatures in the genus Bathynomus on Earth, but had one clear difference from its earthly counterparts.
Its carapace wasn't chitinous, but was covered in something translucent.
‘How fascinating. At a glance, it doesn't look much different from crustaceans on Earth. Except for the carapace covering its whole body...’
Its mana response is quite strong.
It wanted to study it.
As a deep-sea researcher, it had once wanted to study that creature and find out how it differed from the deep-sea crustaceans that existed on Earth.
But.
‘I don't have any tools.’
Right now, it was no longer a human working as a deep-sea researcher, but merely a larva living on the ocean floor.
It had none of the dissection tools it had used when it was human. No microscope. No sample containers. It had nothing it needed for research.
It was just then, as Nereia lamented that it couldn't study the thing before its eyes, no matter how much it wanted to.
‘Now that I think about it... if I can't take it apart and study it, couldn't I study it by eating it?’
Study it by eating it.
If its colleagues from when it was human had heard that, it wouldn't have been strange for them to dismiss it as a lowbrow joke.
But not now.
Nereia had a strange certainty that if it made proper use of the system it had access to, it could learn plenty about the creature simply by eating it.
So.
‘I'll eat well... no, I mean, I'll conduct my research.’
Having made its decision, Nereia lunged at the deep-sea crustacean before it.
The deep-sea crustacean was about 2 mm long. It was more than twice as large as Nereia, which was barely 1 mm, but Nereia wasn't intimidated.
Though it couldn't know for certain, its instincts as a deep-sea researcher told it so.
That deep-sea crustacean before it wasn't very dangerous. At least from its appearance, it didn't seem to have any notable means of attack.
Besides...
‘I survived that damned monster. Am I really going to get eaten by a crustacean barely 2 mm long?’
Thinking that, Nereia clung to the deep-sea crustacean and began feeding.
But.
‘Damn it, it isn't melting at all.’
Nereia clicked its tongue inwardly and muttered.
Until now, its predation had involved devouring its target, then dissolving and absorbing it from within.
Though the crustacean was too large for it to swallow whole, it had thought it could at least dissolve and absorb it, as it had done so far.
Apparently, it couldn't dissolve the creature's unusual carapace, which had an especially strong mana response.
If so, did it have to give up?
‘No, there isn't a perfect creature in the world without a single weakness.’
Thinking that, Nereia began observing the deep-sea crustacean.
Using its fine cilia, it clung to the deep-sea crustacean's body and moved around, learning about it.
And so, Nereia was able to discover...
The weakness of the deep-sea crustacean.
‘A gap. This gap is its weakness.’
No matter how hard a carapace was, if it were a single solid piece, the creature wouldn't be able to move.
In other words, for the creature to move its body, its carapace also had to move according to its range of motion. No matter how hard it was, there had to be tiny gaps to allow its body to move.
The gap Nereia found while examining the deep-sea crustacean's body was just such a gap.
Of course, the gap itself couldn't be called a weakness of the deep-sea crustacean.
Still, finding a gap didn't necessarily mean that it was a weakness.
Even if there was a gap, it was minuscule, formed by hard carapace plates fitting together.
But.
‘That doesn't mean there's no way at all.’
Nereia moved away from the deep-sea crustacean for a moment and looked at itself.
Deep-Sea Unicellular Larva.
Although it now possessed various traits and could no longer be called ‘unicellular,’ that wasn't important, so it set that aside.
What mattered was the nature of its body.
Unlike ordinary creatures, its body was made of cells and was quite soft and pliable. It could push part of its body through even the tiniest gap.
So.
‘I'll squeeze my body through the gaps in its carapace and gnaw it from the inside.’
It had made its plan. Now it was time to act.
There were five gaps in the deep-sea crustacean's body.
Maybe because of its size? Or perhaps because the surroundings meant it didn't need to move much?
The number of gaps was small, but that wasn't a major problem for Nereia.
And so, after clinging to the deep-sea crustacean again, Nereia moved toward one of the gaps it had been watching and worked the fine cilia that had sprouted from its body.
Like an earthworm. Or like a parasite drifting through the sea, it squirmed and pushed its body between the deep-sea crustacean's plates.
After successfully pushing part of its body inside the deep-sea crustacean, Nereia began feeding once again.
Twitch-!
Flail-!
The deep-sea crustacean began to thrash in response to Nereia's predation.
It wasn't from the pain of having parts of its insides dissolved by Nereia's predation. It was merely an instinctive reaction to a foreign object entering its body.
And so, while the deep-sea crustacean thrashed about, Nereia clung tightly with its fine cilia and began dissolving and sucking it from within.
【You have devoured a Deep-Sea Carapace Microbe.】
【You have acquired the Primitive Carapace trait.】
The deep-sea crustacean... no, the Deep-Sea Carapace Microbe's body suddenly went limp, and Nereia saw a system window informing it that it had acquired a new trait called Primitive Carapace.
* * *
Thud! Thud! Thud!
Nereia moved its body this way and that, ramming into the nearby rocks, and smiled with satisfaction.
The Primitive Carapace trait it had acquired this time manifested as a carapace covering its entire body.
And the defensive power of that Primitive Carapace was beyond Nereia's expectations.
Even when it rammed into a nearby rock, it didn't feel much of an impact.
Sometimes cracks appeared, but even those were instantly repaired by the mana it contained.
With this much, it seemed like it could easily withstand the tentacles of a Deep-Sea Predatory Larva.
Of course.
‘It's still not enough.’
Nereia stole a glance beyond the rift through which it had entered the hydrothermal vent.
The turbulent current was still swirling beyond the rift, and the Deep-Sea Predatory Larva was prowling at its edge.
From that, Nereia realized that the creature still hadn't given up on it.
Honestly.
‘It's persistent.’
It should just give up and go find other prey.
Still.
‘I see a chance.’
Nereia hadn't given up, either.
Though it had entered this hydrothermal vent by chance while being chased by the creature, various creatures had settled here, unlike the place where it had first opened its eyes.
If it devoured the creatures here and acquired various traits, maybe it could turn the tables and eat that damned Deep-Sea Predatory Larva.
So.
‘I'll devour as many as I can and get as many traits as possible.’
It couldn't live here forever.
To leave this place and venture into a wider world, it would absolutely have to overcome the Deep-Sea Predatory Larva.
And, just as it couldn't keep running from the Deep-Sea Predatory Larva, it couldn't live a life of always running away.
So. I will grow stronger.
Devour, devour, and devour some more. I will become stronger than I am now.
Yes. I...
‘I will get stronger.’
Nereia muttered that to itself, then moved toward the deep-sea creatures nearby.
* * *
【You have devoured a Deep-Sea Mana-Absorbing Colony.】
【You have acquired the Primitive Mana Absorption trait.】
【You have devoured a Deep-Sea Erosion Larva.】
【You have acquired the Primitive Erosion Organ trait.】
‘I got two?’
Nereia muttered as it looked at the system window.
It felt like it had eaten quite a lot of deep-sea creatures, but had only gotten two traits.
This...
‘Should I be disappointed by the poor return, or happy that I got two at all? I don't know.’
Well, if it had to choose, it should probably be happy.
More importantly.
【Compatibility between possessed traits has been confirmed.】
【Trait fusion is possible for 「Mana Storage Cell」 and 「Primitive Mana Absorption」.】
【Would you like to attempt trait fusion?】
‘Trait fusion? So this is possible, too.’
Trait fusion sounded like something extraordinary.
Especially considering the web novels Nereia had sometimes read back when it worked as a deep-sea researcher, this was practically a cheat-level ability.
So.
‘Execute.’
It was the moment Nereia said that to the system window.
A strange change began taking place inside its body.
The Mana Storage Cell trait it had already had and the newly acquired Primitive Mana Absorption trait melted, then blended together...
【Trait fusion successful.】
【You have acquired the new trait 「Primitive Mana Organ」.】
Having acquired the new Primitive Mana Organ trait, Nereia looked at the Deep-Sea Predatory Larva beyond the rift and said,
‘Just you wait. I'll be back for revenge soon.’
If it kept hunting like this, it would acquire more traits.
And among the traits it acquired, there would be others that could be fused. At this rate, it might soon become stronger than the Deep-Sea Predatory Larva.
Just as Nereia was looking forward to the revenge match it would have in the not-too-distant future...
Another system window appeared in the corner of Nereia's vision.
【Conditions have been met.】
【Evolution requirements have been unlocked.】
It was the unlocking of evolution requirements that would allow it to become even stronger than it was now.