If his mana perception was not faulty, there were more than 30 slimes in his immediate surroundings.
But that was not all!
He could hear the sounds of many more slimes beyond the radius he was able to perceive with his mana.
As such, Nial instinctively backed off, changing his stance the moment he felt that he had retreated far enough.
Listening intently, he heard that a few slimes had toppled to the ground when they had attempted to charge at him and almost squashed each other.
A few of them smacked their slimy bodies on the ground, the sounds ricocheting off the cave walls, causing Nial's ears to twitch.
Yet, only a moment later, all the other noises got drowned as all he could hear was his wild thumping heart that sounded like mini-explosions.
At the same time, Nial grasped his spear tightly as he gathered his courage and tried steadying his heartbeat.
Taking brisk steps, he charged forward before piercing out, only to retreat a moment later.
Penetrating the core of the closest slime, Nial instantly killed it even before he had stepped back.
Since setting foot in the cave, he had already defeated more than 20 slimes.
As such, Nial's senses were on high alert as he listened intently. It allowed him to gauge the distance between him and the slimes based on how far or how near the sounds he could hear were.
This was something he had already learned to do during the last few years in order to avoid running into people when he was forced to leave his home.
It had only been a handful of instances, but when his sister was still well, she had always wanted to play outside with him.
With time Nial had learned to adapt to most situations, and it was only when he was in a very busy and noisy area that problems would occur.
However, with the [Mana Perception] ability, the disadvantage of being forced to rely on the noises around him was nullified.
His biggest limitation had now been removed, and the stronger he would become, the less his dependency on the restriction would be.
Maybe, it was possible for the burden of being unable to see to disappear in its entirety.
That was something Nial couldn't imagine in his current circumstances. Though, now that he had killed some slimes, he realized that it was not impossible to fight, despite being unable to see!
The slimes might not be a threat to him, or even unawakened people, but that did not matter right now!
It all boiled down to how effectively he could visualize what he perceived through the surrounding mana!
He was still learning so his mastery over it was extremely crude, and inaccurate, but oddly enough, Nial had quickly adapted to his new state.
This was quite fast, considering that it had only been three days since he had awoken his origin, and regained the ability to sense mana.
As such, it was evident how fortunate Nial was, even more so because it was a slime dungeon that had manifested in their backyard, and not something more dangerous, like a dungeon filled with goblins.
They were more ferocious and would have attacked him with a much higher speed than the slimes, without any hesitation.
This would have certainly endangered him, and had this dungeon been infested with goblins, he would have died long ago.
He was deep in thoughts and didn't even notice that he was attacking instinctively, using the simple advance-thrust-retreat movement sequence he had trained for years.
There were not many movement sequences Nial had trained in, but the one he knew was amongst the simplest of all.
But even then, it was extremely efficient.
Adding his exceptional senses and mana perception to the movement made him aim with perfect accuracy, hitting the target with most of the thrusts.
Only a few hits missed their target, but that was not a problem because Nial acted quickly enough to avoid being attacked.
This was not exactly difficult, thanks to his opponents' speed.
Nonetheless, Nial wouldn't dare to give the slimes a chance to come even close to him.
Because of that, he would rather react too quickly and prevent any kind of tricky situation before it occurred.
In the end, this was the best he could do, and it worked perfectly fine.
However, that was only the case because the slimes he faced were the most common ones. They were extremely slow had a weak membrane around their body, and had no intention to attack him, to begin with.
As such, Nial had it quite easy to kill the masses of slimes that were slowly moving towards him.
Though they appeared harmless, the visualization of their collective mass was terrifying. Despite the nervousness, Nial had a vibrant smile on his face as he couldn't help but feel happy.
It was not the fact that multiple origin crystals were scattered across the ground, providing him a small fortune, or the adrenaline that surged through his veins that excited him.
Rather, it was the simple fact that he didn't feel useless anymore.
The more he moved using the passive effect of the [Mana Perception] ability, the easier it was for Nial to move without feeling restricted.
During the last few years, he was always forced to pay attention to where he stepped, and avoid bumping into everyone else, who was in a hurry.
While being outside the house with his family, Nial had to be extra careful and focus on his senses to perceive what was going on in his surroundings.
He would always fear getting lost and never being able to find them if he were to get distracted.
All of these burdens were now slowly dispersing, and the accumulated tension in his body was gradually being released.
His stiff movements were now more fluidic while his attacks got swifter and more accurate.
This gave Nial the opportunity to focus on the surrounding mana with a free mind.
Now, he could sense things around him much better and his mind was fast in processing the data it was gathering from the surroundings.
Excitement was coursing through his body, while his entire body was sweating profusely. And despite the exhaustion, Nial felt truly happy!
It was the first time in what seemed like an eternity that he felt like this.
Nial's arms began to hurt because he strained his muscles to deliver the multitude of spear thrusts, and the fat drops of sweat that trickled down his back were a clear sign of his hard work.
Yet, all of this didn't matter anymore, as he smiled brightly while fighting the sheer and supposedly endless number of slimes that were slowly reaching Nial.
Forced to retreat a little, he had to focus fully on every single step, but that didn't seem to be an issue anymore.
Cutting through the air while clutching the crude spear tightly in his hand, he sometimes slashed out with it, killing several slimes at once.
Afterward, he immediately advanced ahead, forcing his way through the slimes.
Increasing his pace with every step, he hacked, slashed, and pierced at the slimes making him realize that all the hours spent in training in his backyard with the heavy stick, and afterward, with the crude spear had not been in vain.
It was now paying off and every kill gave him a renewed sense of confidence- of not being useless, of being strong enough to support his family financially, and of curing his sister.
Being a fast learner, Nial had adjusted to the given situation as quickly as possible.
He moved around, tried to search for the paths with the fewest slimes, only to suddenly retreat.
This confused the unintelligent beasts that were solely following their instincts, giving Nial the chance to finish off the small army of slimes in a matter of half an hour.
Afterward, his arms felt like they were on fire because of the hundreds of thrusts he made in a short amount of time.
They were sore and it was almost as if they would fall off at any moment.
There had been two cases when he had almost slipped on the wet ground, that was covered in the slimy and gooey remains of his opponents.
Thus, his entire body quivered from the immense pressure that weighed down on him while his heart palpated wildly.
Once the battle was over and he had killed all the slimes, Nial just wanted to collapse on the ground and stay there. But, he forced himself to move ahead.
His rewards were lying on the ground, waiting to be picked by him. Thus, after taking lungfuls of air, he decided to pick up the origin crystals that dropped from the masses of slimes he had slaughtered as if they were lifeless objects.
It was still hard for his mind to digest that he had gone on a rampage and killed living beings for the selfish cause of earning money, but at the same time, he told himself that everything had a reason.
The stronger would always exploit the weaker, and Nial was, in fact, the stronger party in the current circumstance.
In the end, the dungeon had manifested in their backyard, and had he not done anything, his parents would have cleared the dungeon anyway.
That was just an excuse, but everyone had to come to a consensus with themselves before killing beasts.
As such, Nial was trying to do this, only to ask himself if the slimes would have spared him had they been stronger than him.
In the worst-case scenario, if nobody would have cleared the dungeon, the slimes would have broken out of the dungeon and emerged inside the shelter.
With dangerous beasts, a dungeon outbreak would be a ticking time bomb and an absolute disaster.
And even if that was not the case for ordinary slimes, it would change once they would mutate, or evolve!
However, that was not something Nial was worried about.
Instead, he bent down on the slippery ground, picking up the first of many origin crystals as he smiled lightly.
'Was I really an optimist all these years, or had I just been forcing myself to be happy enough to make myself feel that I was actually happy?' Nial suddenly asked himself as he realized what true happiness and joy felt like.
It was hard to explain, but he had always felt happy around his family, but at the same time, he couldn't help but question whether this happiness had been real, or just a portion of true happiness?
Nial knew for sure that he loved his family and that he would do everything for them.
Yet, he had always hated himself for having been a burden, useless, and weak.
'Just what had I been doing during the last few years?' He asked himself, his fingers curling tightly around the origin crystal he had just picked up.
On this day Nial changed in his entirety, writing a new chapter in his meaningless life that was about to become meaningful for others, and most importantly, for himself!