While washing myself and my clothes from all of the blood I thought about it over and over again.
The one explanation I came up with in the end was something that would probably be extremely rare or even unique to me. When thinking back to the time I was in the cave unable to see anything I did indeed notice that something was changing, but I just thought it was natural after not using my sense of sight for weeks to even months.
But if my assumption is correct then my eyes didn't just stop working while I was in the cave, rather than doing nothing they could've just gave up on their normal function, my sense of sight and instead focused on the never ending darkness around me.
But my eyes would've only been able to form a mana center and through that absorb the power of the darkness over time if my already existing, but not awakened mana center in my dantian shifted to my eyes. That could explain the change I felt in my body while I was in the cave, but it could probably only happen under special circumstances and if the mana center hadn't awakened yet. I don't even want to think of the consequences that could've occurred if I left the cave and used my eyes before completing the shift of my mana.
"But would my body really just choose to do that?"
I got out of the river and let my clothes finish drying in the sunlight. Looking at my body over the months it had changed and although it was to be expected it still felt weird to look at my body that was now looking extremely muscular, nothing like before. Normally the rate of my growth would've been impossible in my other world, but that's the cool thing in this world. Magic and a limit of growth way harder to reach, it's something I had only been able to dream of, but now that it had become reality I felt like all of my efforts hadn't been in vain at all.
"This has really been more than worth it."
Even if I didn't obtain the ability to use magic through the use of my eyes it was still something I would do over and over again even when I knew of the difficulties and dangers in the cave.
"Well let's try out this new power."
I picked up my clothes and stood there making sure there wasn't anyone dangerous nearby before getting ready to use my newly acquired power. Should I name this power? Well let's just go with something easy for now. I closed my eyes and tried to concentrate myself on the power inside of my eyes. I can feel it!
"Darkness, follow my command."
I opened my eyes and let the power of darkness flow into them. I tried to control the power and got ready to try out the things I was curious about. I looked at a point of grass in under the bright sunlight and tried to turn it into darkness.
The spot of grass turned dark and I was already thinking it was honestly this easy, but then I was confronted with the loss in power.
"Ugh! What happened."
I fell onto the ground and stopped the fall with my arms and stopped the magic. I was sitting on the ground and was heavily breathing like I would after running for a few kilometres nonstop.
"What the fuck went wrong? Why did it take so much energy."
I was looking at the spot of grass and after stopping my magic the grass went back to it's normal bright colour in the sunlight. I was still in thought when I looked at my shadow on the grass behind me and thought of something. It was only a guess, but I prepared myself to use magic again.
"Darkness!"
I concentrated on my shadow and achieved what I wanted. I tried to enhance the range of my shadow and succeeded without feeling as exhausted as before and then I realized what should normally be crystal clear.
"I am so stupid!"
Why did I try to create darkness out of nothing? Although it is possible in this world I thought about magic as something that can turn nothing into something, but that's not the only way to use magic. Why not try to take something already existing like my shadow that is pretty dark already and just enhancing it. It takes way less strength, which only makes sense if you think about it.
I unconsciously didn't use anything from my previous world that would help me. I don't plan on creating weapons that would allow me to just kill someone without any real trouble, because honestly that's just lame and I am already happy that this world doesn't already have crazy op weapons that literally take no skill to use. That would be against the whole point of coming here, but why don't I use the knowledge I had acquired previously that still apply in this world.
Physics, chemistry, biology... these things are probably not really taught as good in this world than in my previous world and I am probably the only one who is able to connect my knowledge of the other world with the opportunities of this world and together create something really fun and helpful. But I can't ever let anyone else know some of the things I know, otherwise this could easily end up in the destruction of normal order in this world.
"Well knowing that, why not try out the other things?"
I continued to try out a lot of things with this power of darkness, like infusing this power directly into other objects like my sword or trying to shoot an arrow infused with my power and seeing if my power would stay on the arrow without direct contact to me. I didn't only try out these things to find out more about this power, although that was the main focus right now, but from my experiences so far I could only guess that using any kind of power connected to your body will naturally let you grow stronger over time just by using it.
And after finding out a lot of incredibly helpful things in connection to this power it was already dark and I was getting closer to falling asleep because using magic still takes a huge amount of stress on the body over time. So I chose to enter the cave and go to sleep peacefully for the first time in half a year.
-At the same time, somewhere in Raiken-
"Princess, your magic is becoming stronger and stronger and your skill with the sword is also getting better and better, I am afraid that in a few years I wouldn't be able to be your opponent anymore."
"Thank you master, but I am sure that even in a few decades master will still be one of the most powerful fighters in the world."
"Well you sure are good with your words, you can go to sleep. We already trained a lot today and the time really flew by so be sure to get a good amount of rest before our next training session."
"Of course thank you master."
The princess ran back inside of the palace and entered her room.
"I don't know why, but why do I feel like something happened to Yori. Why do I keep thinking about him at certain times like these."