After awakening her mana, Arte began to play around with mana whenever I wasn't looking. It was to the point that I started to worry whether she had enough sleep. That was the case today, too.

"Arte? It's late already, get some good sleep."

"Yes~"

She pulled up the blanket to cover her entire body. But the wriggling figure tells me that she's still playing with mana even though I don't see it directly. So I walked over the tent to her side and whispered softly.

"Arte."

"Hm~? What is it, Oppa?"

She peeked out just her head from within the blanket.

'Adorable.'

But I can't be soft on her at a time like this. So I spoke slowly with the most serious expression I could muster.

"If you don't sleep early, you won't grow tall, you know?"

"Fue?"

Then, Arte's eyes shook as if the sky was falling.

"If I stay short, will you marry me?"

"Hm~ that's a difficult question."

I don't think I will marry her either way, but…

'Marrying Arte, is it?'

I don't think there's a problem since our ages are close. However, that’s only true after she grows up.

‘I mean, isn’t she a loli now?’

And even if I have become a child, am I not an undergraduate student inside? I don’t think it’s going to be easy for me to accept myself marrying such a little girl, mentally speaking.

"I don't want to become a criminal, so no."

"Hieeeng… then I will sleep early and grow tall!"

"Yes, yes. Do that from now on, okay?"

"But, um…"

She looked regretful, like someone whose game time was cut short. I understand that feeling well, so I made a suggestion.

"How about this? If you sleep early and follow my words, I will teach you some magic from tomorrow."

"Magic?"

"Yes. It's a very cool trick you can do with mana."

"Oh! Ooh! I like it! Let's do it!"

"Tomorrow, okay? Sleep well for today."

"Okay~!"

She then snuck herself back under the blanket. I used vision skill to see under the blanket just in case, and Arte was closing her eyes tightly with all her might, frowning the entire time.

'Can you even sleep like that?'

I smiled wryly. Then, as expected, Arte snuck her face from the blanket again with a dejected expression.

"Oppa…"

"Why? Can't sleep?"

"Un."

She nodded.

"Are you not sleepy yet?"

"Un."

"Want me to sing a lullaby?"

"Lullaby?"

"It's a good song that makes people sleepy."

"Wow! I want to hear, I want to hear!"

Arte looked at me with sparkling eyes. So I told her to lie comfortably and began to sing. It was the same lullaby that Bianca sang to me back in the lair.

I don't think I'm a good singer. I don't even know the basics of singing.

But if it were the hundreds of songs from this game, then I would have sung it more than tens of thousands of times in the ten years I play.

'If we use the 10,000-hour rule for mastery... then I have mastered the art of singing this game's songs.'

And I sang the songs in so many different ways, too.

'Whether it is to mimick the songs by the original singers, or the modified versions from fans...'

I sang them all.

'One of the reasons is because the songs were simply that good.'

This fact was proven by the many "Let's Sing" videos, remixes, and similar videos being uploaded to the net. Even people who had never played the game would probably know one or two songs by heart.

'And the other reason was because the song helped me go through hard times in life.'

Some were touching. Some were uplifting.

'But every single one of these songs had become an important part of my life.'

It seems like I became immersed in the song before I knew it, but…

'Did it work?'

I looked at Arte after the lullaby ended and saw that she was sleeping with such a blissful expression on her face.

'I'm glad. That's the best compliment I could receive for this song.'

It was a lullaby, after all. I smiled and pulled up the blanket to cover Arte's body properly.

"Sleep well, Arte."

I made sure the countless [Mana Thread] and traps I set were working properly. And then, I finally fell asleep.

***

The next morning.

After doing our usual tasks—me hunting for meat and Arte picking some fruits—we sat next to each other and enjoyed breakfast.

"So, magic is just one application of mana."

I was in the middle of teaching Arte some magic.

"Mana has a characteristic of [Change], so it is widely used in many other ways too. Be it for alchemy, weapon crafting, or for a swordsman to fight."

Arte kept nodding enthusiastically and focusing on my words.

"You probably know this too since you have been playing around with mana quite a bit. But can you demonstrate what you've been doing with mana?"

"Yes! Lookie! I can make rabbits and fishes with mana!"

Arte roused her mana and spread her hands. Then, she formed a cute rabbit hopping around and a school of fishes swimming around in the air.

It was a cute theater about a hungry rabbit's struggle to survive and the school of fish's attempt to guide the rabbit toward a carrot, deep within the sea.

"Wow! Didn't the animals look even cuter than usual?"

"Ehem! That's because I've been playing hard!"

Arte puffed out her modest chest and put both hands on her hips.

"Yes, yes. You did well, Arte. That was great."

"Ehehe."

She smiled sheepishly at the praise.

"So now that you know mana can be shaped like many things, let me show you the simplest magic a beginner can do."

I raised up my right palm and leaked mana out from the tips of my five fingers, shaping them like a thread.

"Wow! What is that, Oppa?"

"This is [Mana Thread]. It's similar to the rabbits and fishes you made just now. But since it's as thin and small as threads, the mana consumption is very small. The cool thing is that you can change many things about the thread. You can make it longer or shorter, harder or softer, thicker or thinner. All sorts of stuff. Because the nature of mana is like this, even the same magic can show a huge difference in performance depending on the person using it."

"Wow! Can I change mana to anything? Can I change anything with mana?"

"One at a time, Arte. But, well, they have the same answer. Generally, yes, you can. But there are rules to it."

"What rules?"

"If you can imagine it vividly, and your imagination actually 'makes sense' that it can convince the world, only then you can change mana or the properties of anything with mana."

"Oh! That's great! But, Oppa, what do you mean? Convince the world? Makes sense? What is it?"

"Hm… for example, look at this fire under the pot."

"What of it?"

"Fire is hot, right?"

"Right!"

"But do you think it makes sense for fire to be cold?"

"Huh? Um… no?"

"Right? So, using mana to make a cold fire, or changing the property of an actual fire to be cold doesn’t make sense. And so, it will fail."

"Oh! I see!"

Arte nodded. She wriggled her body and kept shifting in her place.

'It seemed like she was itching to try it for herself.'

I smiled knowingly at her antics.

"Now, go ahead and try it, Arte. Try to shape your mana like a thread."

"Okay~!"

Arte clenched her fists and replied in high spirits. It seems like she was fully intent on showing me her best self.

‘Let’s see what you can do.’

It was not until later that I was left dumbfounded by the accident that was about to unfold.