Ever since figuring out how to make a light that is warm at the same time, AKA the underground sun, Lan had quite a lot of fun experimenting with his newfound discovery.

First, he tried to replace the illuminating crystal on the first floor, but the result of replacing the mana crystal with an 'artificial sun' of the same size as the floor heating up to the point that it felt like it was the middle of an equatorial rainforest, instead of the mild temperature that it previously had.

Consequently, Lan had to replace the crystal with how it was previously, one with no heating whatsoever.

However, after replacing it Lan found out that with the increase of his capabilities since back when he had just started making mana crystals, the amount of mana contained within a crystal had increased greatly, also resulting in far greater illumination, to the point of being impossible to look at without the supernatural capabilities that Lan had.

So, Lan disintegrated the newly made neutral mana crystal as well. After thinking of a solution for quite a while with no result, the Core's thoughts drifted away from the project and towards the ever-fading human memories.

One of the rare vivid ones that he could remember was when his parents took him on a camping trip to the mountains west of their town. He remembered how they pitched a tent, made a campfire, and how they gazed at the distant stars in the night sky...

'Stars in the sky... Huh.'

Not fully out of his dreamy state, Lan started unconsciously gathering mana at many different points at once, many small crystals forming in the ceiling of the Floor. They dotted the entirety of it, glimmering in the dark.

Gradually, the ambient mana filled them out, Life mana along with Neutral mana making the crystals glow in a greenish light.

The change in the flow of mana snapped Lan out of his state of dreams, and back to reality, facing a scene similar to what he remembered.

Various glowing green crystals were scattered all over the ceiling of the First Floor, illuminating the entirety of it in a gentle glow. Lan stared in wonder while thinking aloud.

'Sometimes the solution comes when you least expect it...'

Lan liked the view, to say the least. The glow was just enough, beautiful yet not too bright. He liked it so much that when he turned his attention to the boss room on the Floor, he removed the single illuminating crystal and tried to condense the 'stars' all over the ceiling as well.

When he tried to do so, he was met with a setback: he had to focus on many things at once to do as he wanted successfully. Still, if he had let that stop him, he would have given up on building his dungeon long ago.

Lan's current mental capacity was far beyond that of a regular human, when he tried doing mental calculations, he could do them at speeds of mere seconds. Most curiously of all, when solving them, he was able to as well, his comprehensive ability far greater than he remembered.

So, when he tried various ways to do multiple things at once, he was getting closer to his goal with each unsuccessful try.

'...What if I try to condense only half of it? No, that won't work... Maybe I need to gather mana beforehand?'

As he went along with his experiments, something new was happening to his thoughts, and suddenly.

'Will that even work?' 'Maybe if I try that...'

A second 'voice' of his thoughts appeared in his mind.

'Who?!' 'What!'

Lan snapped out in confusion, and the voice seemed to be startled as well. Just as Lan thought that he was going schizophrenic, an idea appeared somewhere in his Core.

'Wait...' 'Is it still me?'

His guess was confirmed.

'This is weird...' 'But cool as fuck.'

His conjecture was that there was no second 'voice' in his head, but a parallel line of thinking, which came from one of the novels he read in his human life. After calming down and testing it out in-depth, Lan noticed that he was thinking of multiple things at once, separately.

It was like working on two screens at the same time, paying an equal amount of attention to both. But for a human such a feat would be inefficient, being unable to work well in such a state, for Lan, however, such a state seemed natural, his thinking not being impaired in any way.

'I like this.' 'I'm going to be able to do so much stuff with this!'

It made Lan curious though.

'Is there a limit?' 'How many channels can I split into at once?'

Lan thought back to the moments before he split his thinking into channels, trying to find out how exactly he did it. It didn't take long to find that moment, that mental twist that was needed. Soon enough, a result was apparent.

'I did it!' 'Success!' 'Can I do more?'

And he did it again.

'More?' 'More!' 'More.' 'Correct.'

And again.

'Woah.' 'This is going to be useful.' 'Parallelu Thinkingu!' 'Let's go!' 'Core is better than brains!'

Lan felt wonder in five different ways at his new find. His previously untapped mental power was now put to use efficiently. As an experiment, Lan tried to actively observe both the sky, the surface, and his dungeon at the same time. He succeded.

Lan could actively comprehend the birds in the sky, the forest rapidly growing back from the ashes, and the endless battles for dominance underground. All while thinking in five parallel channels. He wondered if he could take this further.

Yet when he tried to do that twist again, a splitting pain seemed to appear within his very being, when he looked at his Core, to his horror he saw a crack appearing on it. Lan hurriedly collapsed the parallel channels, returning to how he was before.

'What... Happened?'

Lan couldn't find an answer from doing nothing, but he was apprehensive about trying to open the parallel thinking channels once again, so he tried to think logically about the whole thing.

'...Thinking is connected to Mental mana, right? As I gathered more Mental mana and grew bigger, my thinking got faster, along with my mind and memory. So maybe this... Failure is also related to it?'

As he was thinking, he channeled his Mental mana to his Core, along with the command of 'healing', causing the crack to slowly disappear. Once it was gone, Lan tried to split his thinking once again, this time paying close attention to Mental mana.

When he twisted his mind the needed way, the Mental mana flowing from his Core doubled in output. Mental mana that previously was only generated and passively radiated from his Core was now being put to use. Still, Lan remained cautious.

Enjoying this book? Seek out the original to ensure the author gets credit.

'Steady...' 'Let's do it once more.'

After yet another split, around three-tenths of total Mental mana was now being actively used. So, Lan continued the split once again, no splitting pain being present. And then he once again arrived at the point where he thought in five parallel channels at the same time, just like before. Around half of his Mental mana was being used actively.

This time, remembering his previous experience when trying to open the next channel, Lan was cautious and didn't perform the whole 'twist' completely, monitoring the changes instead.

When the sixth channel was forming, the pull on the Core got stronger, and it seemed that the mana used became greater than the amount generated. When such a thing happened, Mental mana that was practically the lifeblood of the Core began getting sucked away from the Core itself, harming it in the process. Lan stopped immediately, the formation dissipating.

This experiment yielded valuable knowledge to Lan.

'Okay, so it seems that the total amount of Mental mana dictates how many channels of parallel thinking I can form at the same time. Each channel consumes Mental mana from the reserves of the Core, but it usually regenerates in time as long as the strain is not too big, but it slows down the regeneration of reserves with each channel.'

Lan shuddered mentally at vividly remembering the pain he suffered when his Core cracked.

'If the output exceeds the generation, I am in danger.'

Lan looked over his finds once again and formed a plan of action.

'Okay, so it seems that as I grow, I will be able to form more channels. But It's not necessary to use all available ones immediately. So, I will only use the amount I need. At the moment four channels are already enough with me having only three Floors. Optimally I would like to have a channel per Floor with one in reserve, but I will see how my growth goes.'

Having finished thinking about that, Lan collapsed his fifth channel, leaving only four. Then, three of the four channels were focused on the Floors, and one was focused on the surface. Observing the sunlit ground, all while being aware of what was beneath it was a refreshing experience.

'Ah... Well, this is new. But the work never stops.'

While Lan was observing the surface, he was already at work underground at the same time. He was currently condensing 'stars' for the boss chamber on the first floor. To finish the process faster, Lan pulled the surface channel to help as well, and soon enough the boss room was lit by many little lights as well.

The second floor needed reworking as well, the illuminating crystal present in the central pillar being obsolete with his new knowledge of Light mana. So, Lan disintegrated the thing and connected the gap that formed inside the pillar. He then opened another gap further up in the pillar, before forming an empty Mana Crystal there.

Following that, he gathered and filled it with Light mana, the crystal now shining in a much brighter light than it was before. But Lan was not satisfied. So, he also began forming 'stars' in the ceiling too. These ones would not be filled with green Life mana, but Lan decided to experiment and fill them with Shadow mana instead.

The result was curious, to say the least. As the dark motes of Shadow mana gathered and were absorbed into the Crystals, the ceiling darkened instead of brightening. The light that shone from the pillar seemed to get absorbed in the darkness that covered it. Now it looked like above the forest on the second floor was a starless night sky instead of a rocky ceiling.

Ironically, the light from the pillar seemed to be even brighter when contrasted with the abyss of the ceiling. The resulting scene on the floor was both eerie and enchanting at the same time, only further enhancing the ambiance.

'This may be useful in the future, as it can be used to simulate boundless darkness or a night sky. Truly beautiful.'

The third floor was next, and the channel of thought that was dedicated to it was currently thinking about whether any changes of lighting were necessary in the first place, as the artificial sun was currently illuminating the jungle of ferns well enough.

'Huh... The only thing that would be desirable would be to somehow make the sun set and rise. But I still lack the ability to make objects move on their own. A task for the future Lan then.'

With no changes being made for the moment, Lan scanned the floor with the channel of thought present. In doing so, he discovered something interesting, something he had been waiting for, for quite a while.

'Finally! The Huntress is forming her Heart Core!'

When he last checked up on the big and proud cat, she was sleeping, and mana was gathering around her. Back then she seemed to be preparing to evolve, which was a bit weird considering that no other Beast or Monster did so.

But right now mana was surging towards her in a process all-too-familiar to Lan. But something was different, and this caused Lan some worry. Two kinds of mana were surging towards her at once.

Lan was worried because the Huntress didn't yet possess a Core, so if anything went wrong, he would not be able to bring her back from the dead. Still, he did not interfere for fear of making things worse.

As Water mana and Shadow mana surged around her at the same time, her organs and skin were slowly breaking down, concentrated mana replacing the fleshy counterparts. Blood seeped through her skin, before evaporating and turning to mana. As she trembled in pain, being seemingly conscious, the currents of mana gathered near her heart, seeking to crush it and turn it into a Heart Core.

The mana gathered and slammed into her heart, the fleshy organ bursting, mana contained within collapsing inwards, condensing into a tiny crystal around which mana gathered, being absorbed into it, growing it.

Once the Heart Core grew to a certain size, other than the mana that was previously contained within her body, Shadow and Water mana also joined the fray, surging towards the Heart Core.

To Lan's horror, the Heart Core trembled, the two types of mana clashing, trying to fill the Core, not being harmonious like in the Mana Crystal that was now an artificial sun, instead fighting for dominance, not ceding a distance to the opposing type of mana.

Under that stress, the Heart Core trembled ever more violently, until suddenly, a crack began to run through it. At this point, Lan was panicking. If the Heart Core shattered, then it meant the death of the Huntress. And it seemed that it would be that way at the rate it was going.

So Lan began frantically searching for solutions, anything to help the cat who he grew rather fond of, survive.

At first, he tried to increase the ambient mana around her in hopes of helping her both fix the Heart Core and maybe overwhelm the conflicting mana. The result disappointed Lan, with the elemental mana instead infecting the neutral mana and surging in turn, accelerating the impending demise of the cougar.

Then he tried to gather Life mana, as it was also a type of elemental mana. This helped a little, with the cracking of the Huntresses' Heart Core halting, even somewhat repairing. But as the Water and Shadow mana kept surging, the Heart Core remained unstable. Lan realized that he was treating the symptoms instead of the cause, and this fight would continue until he solved the problem.

So, as Lan ran out of ideas, only one thing remained which came to the top of his head, his wildcard which he knew was filled with mysteries. Mental mana. Mana which performed miracles, his very own Deus Ex Machina.

If The two types of Mana couldn't reside within a single Heart Core, then it wouldn't end any time soon. But what if there was more than one Heart Core? So, Lan knew what command he should give.

"Form!"

His shout echoed throughout the boss room, although Lan didn't notice the fact that he spoke aloud for the first time ever since he became a Core, instead focusing on the result of his attempt to save the Huntresses' life.

He watched as with surging mana, yet another Heart Core began forming. A tiny crystalline seed appeared next to the fully formed yet unstable Heart Core. It absorbed the abundant mana, and it didn't take long for it to grow to the same size as the other one.

As if sharks smelling blood, the elemental mana surged towards it as well, but Lan would not allow for it to get destabilized as well.

"Oh no you don't!"

As the Huntress herself seemed to wince and get pressed into the ground with some kind of invisible pressure, only Water mana surged into her second Heart Core. With no 'competition' present, it was quickly filled up, beginning to glow in a bluish light. The first Heart Core on the other hand had Shadow mana which now overwhelmed the Water mana that was present, fully occupying the vessel.

As both Heart Cores became full, a resonance formed between them, as if both Cores, although having different types of mana, worked together. Both Water and Shadow mana, with Life mana as a foundation, filled out the whole mana-formed body of the cougar, filling it out, carving out the Mana Circuits, flowing... and mixing.

The mana that categorically refused to mix inside of the Heart Core now became whole, like ink staining the water. Quite literally in this case. Light Blue mixed with the Dark, forming a Dark Blue mana. Patterns of the same color began carving themselves on top of the fur of the Huntress, being both subtle and gentle, flowing along her skin and fur in a symmetrical manner.

Finally, the Huntress awoke from her agony, shakily standing up to her feet.

Suddenly, shadows began to gather around her and water droplets began to float midair. And then... The water and shadows mixed.

The water became darkly colored as if the droplets of water became droplets of ink. As a sheet of water formed in front of the Huntress, shadows mixed with it, making it into a dark curtain that was impossible to see through. Interestingly enough, this lack of visibility didn't seem to apply to the caster herself.

'Sigh... Mana shenanigans. The more I know, the more remains unknown... I'm glad she is alive. I wasn't sure it would work.'

As Lan observed the big cat experimenting with her magic, the irony of cats being afraid of water was seemingly lost on her, to his surprise he felt a tug on his mental connection, one leading to the Huntress herself. He 'accepted' the 'request'.

Intents and thoughts were transmitted from her, along with a somewhat feminine voice.

"Thank you oh Master of the Hunt. I thank you for saving my life."

After making such a statement, the female cougar went to sleep, leaving Lan dumbfounded.