That time I was reincarnated as a snake (Tensura)

More than a month after the explosion in the capital Eldoria, tensions between the kingdom of Eldoreth and the Sorcerer Dynasty Sarion were on the rise. This was because the elves sent by Sarion to rescue a kidnapped elf, seeing their compatriot being auctioned off as mere merchandise to the filthy human nobles, took radical action without prior orders, without thinking of the consequences.

Once the kidnapped elf was rescued with relative ease, thanks to the magic of the rescue team, they proceeded to escape from the capital. Not before leaving behind several magical objects with an incredible explosive capacity, which were detonated from a distance.

The radius of the explosion was a couple of kilometers, destroying everything in its path. Not only did this destruction cause the destruction of a significant part of the noble district, but also, being close to the slave auction, the shockwave spread further, seriously injuring a large number of common people who had nothing to do with all this.

Clearly the elves intended to take revenge on the humans for daring to kidnap an important member of their kingdom.

The explosion was an ultimatum: "Don't mess with us or this is what awaits you!"

Although many nobles died, they were not all the nobles that the kingdom had. Moreover, the royal family was not affected due to this event, so the kingdom had no problems in organizing itself. Outraged by this act by Sarion, the nobles demanded that the king wage war against the elves, ignoring the fact that they were responsible for everything.

The king, though he wanted to avoid trouble with Sarion, was unable to oppose the members of his court who demanded war. He could only bite the bullet and, with swift actions, established a powerful task force consisting of over fifty thousand soldiers recruited from across the kingdom.

Among them were thousands of knights, hard-earned by the king and nobles, who would serve as commanders of the expedition, as well as hundreds of mages who graduated from the Agile magic academy. These were recruited compulsorily, as they had enjoyed the benefits, now it was time to repay the kingdom for it.

The army had a large number of adventurers in its ranks, because although they were part of the adventurer mutual aid association, this organization was not free from the control of royalty. Therefore, the members could only heed the summons or they would be punished by the law of the kingdom.

It wasn't like in the future, where the Free Guild was only responsible to the council of nations, and no kingdom could exert authority over it. For the most part, adventurers were free from conflicts between nations.

Although the nobles wanted to start the war quickly, they had to wait several weeks, not only for the mass recruitment of soldiers, but because in principle the kingdom of Eldoreth and Sarion did not share borders. Between them there was a human kingdom called Zarath, although small compared to the previous two, it was a fairly rich kingdom.

This was because their kingdom was located next to a mountain range southwest of the Jura Forest. The mountains were a huge source of mineral resources, which were exploited by the kingdom of Zarath and later sold to the other human kingdoms, as well as to Sarion.

The existence of the kingdom of Zarath, due to its lucrative dealings with Sarion, represented a potential danger if the kingdom of Eldoreth wanted to cross it to reach Sarion.

King Aldric Elion Thorne Eldoreth could only bribe the kingdom of Zarath to allow the movement of his troops into its territory and remain oblivious to the whole affair.

Happy for the benefits, King Thalor Varian Zarath agreed. After all, it was none of his business, whoever won, he would reap the benefits.

With everything organized, the expedition force left the capital in the direction of Sarion. Calculating their speed and rest times, they would reach the borders with Sarion in just over three weeks.

As for Sarion's side, they remained silent all this time, as if they cared nothing about this so-called war.

-Kai's POV-

Two days after the explosion in the capital Eldoria, Mira and I arrived near the fortress city GreenRock. Instead of heading straight to it, we arrived at a place several kilometers inside the Jura Forest.

After one more shadow-moving journey, we entered an underground cavern, hundreds of meters underground. There was no conventional way to enter it, it was completely closed. It would only be accessible to us or someone using spatial magic.

This was a natural cavern I found a while back. As a Batman fan, I always wanted to have a secret underground base and since I could in this world, I made it a reality.

The cavern was originally small. It was only later, when I began studying magic, that I set out to renovate it. Using various magics and my great firepower, I managed to make it into what it is today, a cavern over a hundred meters high and with a surface area that can accommodate a dozen football fields, with its entire structure reinforced with magic to prevent collapses and with defensive barriers installed to prevent anyone from entering besides Mira and me.

This project had taken up most of my free time between my practice, studies and Phersu supervision, but I had no regrets about it.

Who doesn't want to have their own batcave?!

Unfortunately mine wasn't that great, it was just a giant cave, which I mainly used as storage for many things I stole over time.

I was planning to make use of it when I returned from my stay in the capital a few months later, but due to certain idiots, I returned much earlier than planned.

Mira and I got inside. We went to a corner of the room and I got to work.

Casting some simple earth spells, I created some stone tables for test subjects. "Could you get the werewolf out?" I said to Mira.

She just pulled it out of her shadow. It's nice that your partner is a portable storage unit.

Even with my efforts to learn how to do it, I have not yet succeeded. Although I can introduce small objects, when it comes to large things, sometimes I lose control and the objects get lost.

The werewolf emerged from his shadow in an unconscious state. He had put him to sleep so he wouldn't be a nuisance during the journey.

With some shadow whips I conjured, I placed him on the table and proceeded to tie him to it.

"Remind me, why did you want a werewolf?" Mira said as she watched me doing this.

As I continued to prepare some things for the experiment, I answered him.

"Do you know how long I am?" I said without turning to look at her.

"It should be about twenty-six meters, I think. Why the question about nothing?" she said doubtfully.

Yes, you heard that right, my current length is twenty-six meters, equivalent to an eight-story building. I have reached a size comparable to that of the Storm Serpents without having evolved, although my growth rate slowed down the longer I grew.

"Right, you should have realized by now that it is extremely difficult for me to do some things delicately. Although I can now use various magic to help me, I still have some problems," I said as I finished preparing several magic circles.

"And what does a werewolf have to do with all this?" Mira said, rolling her eyes.

Seeing her like that, I could only sigh helplessly.

"You know, Mira, you should come with me to my study sessions more often, having more knowledge will help you a lot in the future," I told her, exasperated.

"Don't even think about it, I don't like studying, I'll leave that to you. That's what you're good at," Mira said quickly.

As you can imagine, it's not that I haven't tried to share my knowledge with her, it's just that she's very lazy when it comes to studying. In the many times I tried, it only took a few hours before she got bored, got desperate, and went somewhere else to do something else.

If I have to describe Mira, I'd say she's more of an action girl. I don't mean she's dumb or reckless, obviously not. She's very capable in fighting, she's just not the type of girl who likes to sit around and memorize information.

Plus, with me around, it's easier for her to ask me for advice if she needs it. If she has any questions, she uses me as her search navigator.

I rolled my eyes at his response.

"Simply put, werewolves are born with the intrinsic ability of Beastialize, which allows them to alter their appearance between their Beast Form and Human Form. That's what I'm after, I want to understand how it works and replicate it for myself," I said to Mira.

"Isn't there an easier way? I remember you mentioned that if a monster evolves with a strong desire to change its appearance, that will happen," Mira asked.

"Yes, but that would only change my body into a human form, and that would lead to losing the advantages of my current large body, such as my great physical strength. That's why I wanted a werewolf; if I can understand its ability, I don't have to choose between one body type or the other," I said proudly.

"Could you help me bring a living human and a Direwolf here?" I asked her with a smile.

To which Mira responded with a pout. It was only until I used the puppy dog eyes that she agreed.

"While she looks for those control samples, let's see what we have here," I said, focusing my gaze on the tied-up werewolf.

Making use of my magical perception, as well as several magic circles specialized in analysis, detection, and perception, I proceeded to carefully study his body.

Although his own magicules stood in the way of mine in analyzing it, thanks to me being much stronger, resistance was futile.

"Mm… interesting. In this form, which should be his hybrid state between beast and human form, I can see how his body functions like a normal human's. Even his ears on top of his head function the same as a wolf's ears would, but they connect to his brain like a human's, only on top of his head instead of on the sides of it."

"It's similar to the human body being a computer and the animal parts being peripheral devices similar in function to the originals, but with greater capacity. I should wait for Mira to bring those guys over so I can compare better instead of just making assumptions," I said to myself.

A few minutes later…

Mira brought a muscular human wearing leather armor, as well as a large Direwolf, possibly the leader of a pack. Both were unconscious.

"There you have it. It was a coincidence; I went looking for the Direwolf when I found a pack besieging a group of adventurers. I killed all of them except for these two, who were the strongest of their groups," Mira said proudly.

"Great, you did that really quickly," I said.

Without wasting any time, I placed them both on other tables next to the werewolf.

While I focused all my concentration on them, Mira, for her part, not wanting to get bored watching me do my job, went to another area of the cave to do whatever she wanted.

I spent the next few days trying to understand what was in front of me.

…

When I was reading Tensura's light novels, I was always struck by a few details. Among them, when I read about the origin of the races of this world, which were created by Twilight Valentine, at Veldanava's request, I always had a doubt.

How did he hybridize humans with monsters?

I understand that he was the prototype created by Veldanava himself, a perfect being, having an immortal physical body as well as a powerful soul. All right with that.

I can also understand how the high dwarves, high elves, enki, and mermaids came to be. They are nothing more than spirits of the four elements that possessed the bodies created from Twilight Valentine's flesh, I could compare it to software that was put into hardware. Nothing complicated.

As for monsters, one could say that they are concentrated magicules that give rise to souls protected by a physical body entirely constructed of magicules. I believe that it is because the souls of monsters are formed out of nothing by magicules that their quality is lower than that of humans. The souls of humans, I speculate, are already existing souls in the cycle of reincarnation.

In my opinion, a monster's body is magicules simulating the properties of a physical body, such as the nervous system, blood system, and digestive system. Obviously with changes to function with magicules, so there is no real DNA as such. When two monsters give birth to a child, it is known that their magicules combine to give birth to the new being. That means that the magicules contain "genetic" information.

So, my question is:

How did he do it? How did he combine a physical being with no reserves of magicules, a human, and a being purely made of magicules, a monster? Did he implant the physical data of humans into magicules and then fuse them with the magicules of a monster? Did he create a physical body of flesh and blood, without magicules, for a monster, which adapted to its monstrous characteristics and then reproduced them with humans? Perhaps only Twilight Valentine and her disciples/children know how he did it.

I may not be able to give an answer to these questions, but at least I was able to understand some of the essence.

Through tests I performed on the werewolf in its various forms, which I made it take using my mind control magic, I compared its forms to those of the human and the Direwolf. I was able to understand the essence of the Beastialize skill. Basically, it works as an information store, somewhat similar to my chant nullification skill. It stores all the data of the individual's different forms. In the case of werewolves, it stores the information of their beast and human ancestors, as well as generating the transformation sequences to go from one to the other, quickly and almost subconsciously.

So, according to my research, it should be very easy for any monster to acquire a similar ability. After all, they are all magicules constructs; they should be capable of such a thing easily.

Not quite.

Doesn't this method remind you of something? Something very important for a monster to become strong.

Exactly, evolution.

If a monster could turn its body into whatever it wanted, it would essentially no longer be limited by its own body. If it could no longer contain any more magicules, it would just have to change into a body that could support them.

Normally, when a monster evolves, it is the voice of the world that helps it through this transformation process.

I can only assume that it is easier to take weaker forms to stronger ones, perhaps due to lacking the information of beings stronger than oneself or the magicules necessary to form the stronger body.

Look at the predatory ability: by consuming another being, the ability analyzes it and with the data it can replicate it or even enhance its traits. It practically opens the doors to infinite possibilities. That's why it's so OP.

I guess when the first werewolves were born, inheriting both human and beast information, the voice of the world said, "Well, take both," and that was it, they acquired this ability.

Does this information help me to have human form? Yes, it does.

According to my hypothesis, as long as I can convert my current body into a functional human form, while retaining the data of my current snake form, I should be able to acquire an ability similar to Beastialize.

Since I didn't want to lose this body, I had to place great importance on studying myself and understanding myself before beginning the transformation trials.

I had to be very thorough about this; I needed to understand the workings of both the human body and my snake body at the level of a doctor, or at least as close as possible without any relevant information, in order to minimize the risks.

Three weeks later...

"Hmph... I think I'm ready," I let out a tired sigh.

If I had a human body, I'm sure I would have dark circles under my eyes from fatigue.

After not sleeping for weeks and using thought acceleration all this time , which had been enhanced over time, it was no longer just a hundredfold increase, it was now at least a two hundredfold increase in my thought processes.

That was both good and bad news, since for me these three weeks were equivalent to almost ten years, far exceeding the time a doctor spends studying for his or her degree (I'm referring to university, not the time since preschool).

Through trial and error, as well as previous knowledge I had about the human body and its biological processes (thanks to the fact that one of my older sisters was a doctor and, in order to understand when she spoke to me with her terminologies, I decided to learn a bit from her books), I could now be considered to a certain extent Dr. Snake, not to be compared to that mad scientist from Naruto. Although if I continue with my experimentation mentality, which partly attracts my curiosity, in a few more centuries, I don't rule out that I will end up as a mad scientist.

But seeing the ultimate fate of all the mad scientists across multiple worlds, I better try to keep my cool and not fall down that rabbit hole.

…

Now the time had come for the final stage.

Having collected all the information about my body, as well as that of the human, creating the data of a theoretically possible body with the help of the almost omnipotent magicules, as well as the process of transitioning from my current body to that theoretical body, it was time to try to transform.

For this grand event, I had set up a barrier at my base capable of containing the magicules within it. While I continued with my analysis, Mira helped me by hunting down many strong monsters and throwing them inside the barrier.

Little by little, with each monster added, the inside of the barrier continued to become saturated with magicules. Given enough time, it would surely begin to spawn monsters. All of this preparation was done to give me enough fuel to acquire the skill, or, failing that, trigger my evolution, which would improve my chances of acquiring it.

Mira and I were outside the barrier.

Without any words from either of them, I dove in.

Inside I could feel a sort of dull pain all over my body. If it wasn't bad, it was my body warning me of the damage caused by the high concentration of magicules. I decided to ignore it; this damage would only make me stronger thanks to my Adaptive skill.

I took a deep breath of magicule-laden air. I could feel some irritation in my throat.

"Okay, let's do that!" I shouted with my head looking up at the sky.

"That?" Mira said.

"Isn't it clear?" I said with a smile.

"Let's Conb… Cough… Transform!" I quickly corrected my slip.

I released all of my aura, which I normally contain most of the time. I may not be in the ranks of the strongest in this world, but the concentration of my aura has already reached the level of being able to generate weak monsters given enough time if I don't keep it contained.

Maintaining a strong image of the process of turning my body into the theoretical body, at the same time I reproduced from my memories in my mind an epic musical theme such as "Sorairo Days".

With all my will I drew all the magicules within the barrier to my body.

A powerful whirlpool of magicules formed around me.

My body slowly changed, gradually shrinking, my imposing twenty-meter frame becoming smaller and smaller. Meanwhile, at my sides, arms and legs began to emerge. My snake head with its flexible jaws slowly changed into a new structure, similar to that of apes. My strong scales that covered my entire body were slowly replaced by clear, smooth skin. My once long and powerful tail disappeared completely, replaced by round, firm buttocks. Locks of ebony hair sprouted from my head, which took on a short, stylized shape. Finally, my cold, reptilian slit eyes transformed into bright ocean-blue pupils, capable of fascinating the ladies.

My body had almost successfully changed into human form, only the finer details of the interior were missing. But, the familiar feeling of evolution appeared again.

I quickly found myself surrounded by a cocoon of magicules.

My body demanded sleep to complete the process.

"Not this time! I don't plan on sleeping! I won't let you take the credit, I'm going to finish it on my own!" I shouted determinedly inside the cocoon.

Using all my will, I tried to stay awake, finishing my body transformation. Unfortunately, little by little my mind fell into a deep sleep, slowly losing control over my transformation.

In the depths of absolute darkness, a bright red eye suddenly opened and with it a roar resounded.

"GRROOOAAARRR!!"

Just as I thought I would fall asleep, I could hear a powerful roar inside me, a roar that conveyed strength, ferocity, and an incredible spirit of dominance over everything. That roar brought me back to consciousness.

'What was that?' I thought, alarmed.

Not finding the answer, I decided to ignore him. Slowly, a smile appeared on my face.

Playing the song in my mind once again…

"Let's get this over with!" "Aaaaaaaaaaaa!"

I continued to control my transformation manually, doing my best to finish before my evolution did. With my shout, more and more magicules were drawn into my cocoon, until I heard it.

Extra Skill: Successful acquisition of Transformation.

"Hahahaha, I beat you!" I shouted proudly.

I had done it, I acquired the ability to transform through my hard work and not through evolution. Only when all the magicules within the barrier were exhausted did my cocoon explode, revealing the new me.

The skills Water Pressure, Water Shape, ... have been integrated into the extra skill Water Manipulation.

My appearance was similar to how I looked in my old life, but more attractive. My current body was more toned and muscular, my hair, which was once dark brown, was now a midnight black. My eyes were blue like the sea, in them, sparkles like stars flickered like the starry sky.

But most importantly...

"I don't have any clothes, I forgot them!" I shouted at the top of my lungs.

"Are you embarrassed to show everything?" Mira said with an amused grimace at my reaction, but happy that I was successful.

Quickly, using my new Transformation ability, I returned to my snake form, although now my body was different than before the evolution.

My overall form, which had previously resembled a black mamba snake, now looked similar to a cobra. I now had hoods near my head, several spikes protruded from my back, and my head now featured horns, somewhat similar to those of dragons. On top of that, as a custom when I evolved, my size had increased, from the previous twenty-six meters to the current thirty-five meters. I could give a dragon a run for its money in sheer physical power, though I wouldn't, I have my magic and skills for something, but who wouldn't enjoy a fight of flesh on flesh?

Something interesting was that I had finally lost all traces of the blue color on my body, except for my eyes, which were now completely black. Looking between Mira and I several times, a smile formed on my face.

"I think we match better now, don't you, Mira?" I said to her while laughing.

She smiled in response and joined in the laughter.

A black panther more than ten meters long and a snake three times its size were laughing happily together deep in a gigantic cave.

__________________

Author's notes:

Kai evolves again, along with the acquisition of the long-awaited human form. His skills acquired over months, thanks to the large amount of magicules, finally gave rise to the Water Manipulation ability that Kai so desired.

The conflict between humans and elves begins, who will win? Yes, I know that humans don't stand a chance, but I'll try to make this subplot interesting.

I wrote most of this chapter while listening to "Sorairo Days" on loop. If you didn't feel the excitement I felt while reading it, it's because of my lack of skill, because while I was writing it imagining the scene in "Tengen Toppa Gurren Lagann" style, while listening to the song, it was epic.