If his senses weren't failing, there should be more than 30 ordinary slimes left.
Additionally, there was also the Slime Boss that was approaching him from the deepest parts of the cave at a fast pace.
Nial concluded that the Slime Boss would arrive in front of him before he could defeat the remaining slimes.
As such, he entered a defensive stance, with the spearhead pointing towards the Boss, awaiting its arrival.
Only a moment later, Nial's mana perception recognized the fast approach of the large slime that was at least ten times the mass of the common slimes.
Thus, without hesitation, he adjusted his stance once again, before thrusting out with the crude spear the moment the Boss Monster was close enough.
There was still a meter of distance between them, but with a short step, and the spear thrust, Nial crossed the distance in the blink of an eye.
He hit the target, which was confirmed when he heard the squelching sound of his spear piercing through the slime.
A moment later, he wanted to instinctively retract the spear but strangely he met some resistance.
The moment the spear pierced through the thick membrane of the slime, it clung to the spear in an attempt to prevent it from being pulled out.
Only by using his entire accumulated strength was it possible for him to retract the spear.
Its resistance gave Nial an idea about the Slime Boss's strength, forcing Nial to retreat with fast steps.
Through this short encounter, Nial understood some of the Slime Boss's traits.
Though it was stronger than the other slimes, it was not a life-threatening opponent.
First, it was slightly slower than him, and slightly weaker, if one were to compare the strength it used to cling onto the spearhead with physical strength.
At the same time, its defenses were extremely strong and much higher than Nial had expected.
It was obvious that the Slime Boss was stronger, and he already knew that it wouldn't be that easy.
However, to think that his spear thrust had been rendered useless made him feel a bit disappointed.
Fortunately, that feeling dispersed only a moment later because he had no time to waste thinking about his failure.
Instead, he had to find a way out of the predicament.
Just as he wanted to try slicing out parts of the Slime Boss's membrane, and slowly close the distance between the spear tip and the core through this tactic, Nial perceived several sounds from behind him.
They were ordinary slimes that were gearing up to attack him from behind.
Yet, rather than being a formidable force, they were more like annoying obstructions, and without minding them too much, he swiftly pierced out with his spear, killing them one after another.
Afterward, he moved around the corpses, while trying to find the best spot to start the onslaught of attacks on the Slime Boss.
However, just as he raised his spear, the Slime Boss jiggled over the corpses of its now dead comrades and devoured them.
As Nial watched in a daze, its size increased by a small margin. His face turned ashen white as he gave it a disbelieving look.
'It can devour its brethren and grow?! What kind of cheat is that…?'
Gritting his teeth, Nial now realized that he shouldn't kill the remaining ordinary slimes first, even if they were to attack him.
This was annoying, but also something Nial couldn't risk after he had witnessed the Slime Boss's ability.
His mind rattled while trying to think of a solution to attack the best, but there was not really an opening for him.
As such, Nial gave up on attempting a perfect attack.
Halting his retreat, he switched to attacking with slashes in order to overwhelm the Slime Boss. Using the sharp tip of his spear, he sliced at the Slime Boss's outermost membrane, cutting out small and uneven pieces.
This seemed to work, and the small parts wriggled on the ground for a bit before spilling over the floor a moment later.
Nial had already noticed that Slimes were comparable to jellyfishes, and it was their core that held their form together.
As such, their entire body was made of an unknown liquid that enveloped the slime's core like multiple layers of a membrane.
Nevertheless, as every individual layer was relative weak, Nial's spear was not strongly resisted.
Thus, he was able to swiftly slash out, using multiple approaches to cut at its big, slimy body so as to easily reach the core.
This seemed to work in the beginning, but once a certain mass had been cut off, the liquid membrane became firmer and stronger, resisting his attacks more and more.
It was still possible to cut through the membrane, but it took him a lot more energy than before. And, the short fraction in which he was forced to halt his movement gave the Slime Boss enough time to counterattack.
That was bad, and when it happened for the first time, Nial had almost been overwhelmed.
After the first time, he became more careful, knowing that a single mistake would be his death.
If the Slime Boss reached him, it would try to gobble him up in its liquid, devouring him in his entirety.
No way would he want to end up like that which made Nial try harder to kill the Slime Boss.
They had been fighting only for the last ten minutes, yet Nial's back was drenched in cold sweat.
Though it was disappointing, he did not let himself be overwhelmed by the inability to kill the Slime Boss within that duration. Nial's body which had grown tired was moving to inflict more damage and have fewer wasted movements than hours before.
When Nial noticed this, he was astonished, and it gave him enough motivation to exceed the limits of his body, which he thought to have already surpassed, once again.
The moment Nial made this decision, he moved subconsciously as he lashed out with his spear once again.
However, this time he targeted the slime's large core without hesitation as faint currents of mana enveloped the spear tip.
Nial had attempted to use faint traces of mana within his body to lead it through his body towards the spear.
Unfortunately, that hadn't been useful enough as it barely strengthened him.
Thus, Nial inserted the last ounce of his strength and mana in this seemingly simple spear thrust that would also be his last attack.
After he had inserted his mana, the spear began to vibrate wildly making Nial almost lose his grip. He was barely able to hold it as faint cracks began to spread out from the blade.
The spear was not equipped to make use of mana, but Nial had ignored this, knowing that he had only one last chance to attack before he would be forced to retreat.
As such, the moment the mana inserted spear tip pierced through the slime's membrane, Nial heard faint crackling sounds as a cobweb-like pattern spread over it.
Yet, instead of breaking apart, the mana enriched blade seemed to ignore the highly resistant liquid that enveloped the slime. It swiftly pierced into the slime's core, shattering it, followed by the spear tip that broke apart as well.
A second later, the liquid that had been held together was released, splattering on the ground.
The Slime Boss's body exploded throwing a sticky liquid all around which made Nial slip and lose his balance.
His body was on the verge of breaking apart, and he fell to the ground. While gasping for air, he sensed that the large slime's body was disintegrating into countless particles.
Following this, he could hear the clinking noise of origin crystals falling to the ground.
However, even after hearing this sound, he didn't move because his body didn't want him to. He simply lay on the rocky, uneven cave floor that suddenly felt like a bed made of the softest feathers.
At that moment, the passive effect of his [Mana Perception(poorest)] ability allowed Nial to perceive something. It caused him to feel like his tiredness had been washed away as he mumbled,
"It really is a permanent dungeon...what a surprise...was about time for our family to have some luck, after all…''