Using the Body Flicker Technique, Seimei arrived at the location of his father's hidden research lab secretly and silently.

His father said he had some important research results to share with him. Although he didn't explicitly state what that was about, Seimei knew that either the research subject or the research process had to be at least morally gray.

Otherwise, he would have directly mentioned what the research and the results were about.

The problem was that his uncle, Hashirama, was nearby when his father mentioned it. If Hashirama heard anything about the morally gray shit, he would cause Tobirama, his father, loads of trouble, along with a tremendous headache.

He might even utter his famous line, "Seal it."

Seimei lost count of how many times Hashirama had forced his father's projects or newly developed morally gray or deadly Ninjutsu to be locked away in the Sealing Scroll.

Don't be fooled by Hashirama's goofy smile and forgetful nature. His analytical skills are quite formidable.

And since Tobirama had Hokage duties to handle, which would have taken all day, he didn't even have the luxury to take Seimei somewhere else, cast the Sound-Blocking Barrier Seal, and talk about it.

Why?

Because that was a waste of time.

Seimei would learn about it when he visited the research lab anyway.

So, here he was, after entering the deep forest on the outskirts of Konoha, Seimei finally approached the inconspicuous sealed door of the hidden research lab.

The whole area was covered with countless seals to prevent the research lab from being discovered by any Shinobi other than those who had the permission to enter.

And only Tobirama and Seimei had the required Fuinjutsu Seal combination to discover the door to the lab and actually enter it without being ambushed by countless vicious traps and Cursed Sealing Techniques (Juinjutsu).

Now, even if you entered the secret hideout, it would have been useless.

The 'hidden research lab' you had discovered after finding the door and enduring deadly assaults enough to kill or severely injure a Kage-level ninja was nothing but a decoy.

After all, the true hidden research lab was located underground.

And you needed another secret combination of password seal and spatial teleportation seal to enter the lab.

Truly cautious and sophisticated.

Other people can forget about intruding here.

But hey, in this world of ninjas, you could never be overly cautious.

To survive here, you not only needed to be overpowered and brave, but you also needed to be extremely cautious, like a certain cautious hero summoned by an idiot goddess in one of the anime Seimei used to watch in his previous life.

As one portion of Seimei's mind began traveling to the wonderland of random thoughts, he finally arrived in front of the spatial teleportation seal and poured chakra into it.

Once the seal was fully charged, Seimei touched it again, which triggered the seal and engulfed him in a mysterious blue light.

The blue light intensified, causing the surrounding space fabrics to tremble.

Then, the light dimmed and slowly disappeared. And along with it, Seimei's figure vanished from the spot as well.

-----------

In a dimly lit room of an underground base, strange seals suddenly glowed with a blue hue and began affecting the surrounding space.

Suddenly, the blue hue glowed even more brightly, causing the surrounding spatial fabrics to come alive.

And then, the light dimmed, revealing the figure of a nearly 11-year-old child.

The child slowly opened his ocean-blue eyes, which glowed majestically for a while before returning to normal.

It was none other than Seimei.

"The more I traverse the space-time tunnels using these seals, the more my understanding of space seems to deepen."

"Somehow, it also helped me control the ocular technique, which I awakened after my Tenseigan evolved to LV3, better, although space and the fundamental force I control through my ocular technique don't have any direct connection."

"No…I am wrong."

"They do have a direct connection, but it is awfully abstract."

"Gotta dive into the Theory of General Relativity to even discover the connection there."

"Hehe…forget about it for now."

Then, Seimei stepped out of the room and passed through several doors before finally entering the main laboratory.

The main laboratory was as big as two full-sized football stadiums. His father truly went all out to build it.

As Seimei walked, he quickly found Tobirama tinkering with a vibrant green liquid in a test tube.

Beside him was a table full of Petri dishes, a microscope, and several test tubes containing green liquids of different shades, each labeled with a different number.

Tobirama, sensing Seimei's presence, said without even looking up, "You're here? Good."

Seimei nodded, "You wanted me to come here, Father."

"You didn't even say it in front of Uncle. Must be something that could be sealed away once he found out about it."

Tobirama let out a dry chuckle and replied, "He would indeed do something like that."

"But I must still continue this research."

Seimei had already arrived near Tobirama and asked curiously, "What is it about?"

Tobirama finally put the test tube in a holder, looked toward Seimei, and said, "It's about Sharingan. More specifically, it's about Mangekyo Sharingan."

Hearing this, Seimei suddenly froze.

He looked at his father with a bewildered expression.

Seimei asked, "You didn't capture some Uchiha to conduct human experiments on Sharingan, did you?"

Seimei activated his Tenseigan to check the lab carefully once again.

And sure enough, there were indeed nine pairs of three-tomoe Sharingan and one pair of Mangekyo Sharingan in a faraway corner within the lab.

Those pairs of Sharingan were submerged in a preserving nutrients solution, which would keep the eyes fresh and alive for at least a century.

However, hearing Seimei's question, Tobirama's face instantly darkened.

The sound of his voice lifted several notches, and he retorted, "You brat, what do you take your father for?"

"Would I harm an innocent fellow Konoha Shinobi just for my research?"

"I may be a bit prejudiced when it comes to those stiff Uchiha guys, but I'm not that petty."

"I admit I have a lot of Sharingan, but those are just my spoils of war from the Warring States Period, when we had to fight with practically every other Shinobi clan, except for our allied clans."

"But that was in the past."

"Now that we have formed Konoha, we are a big family."

"Do you think I will kill them and pluck their eyes just because they have the surname 'Uchiha'?"

"Am I that kind of person?"

Tobirama finished speaking and glared at Seimei.

Seimei, on the other hand, let out an awkward laugh and said, "Hehe…don't be mad, father."

"How could you be such a person without any morality?"

"I was just joking earlier."

However, Seimei thought in his mind…

I want to say something, but I'm not sure if I should say it.

But that aside, just how many Uchiha ninjas did you kill, father?"

Those owners of Sharingan must be cursing at you right now.

Meanwhile, Tobirama's lips twitched as he saw Seimei flattering him with a fake expression.

He could only sigh and say, "Forget about it for a moment."

"Did you read the notes I gave you that described the evolution of Sharingan?"

Seimei nodded and gestured for Tobirama to continue.

Seeing this, Tobirama continued, "Then you should know that the ultimate evolution of Sharingan leads to the awakening of the Mangekyo Sharingan."

"It's the ultimate and final evolution of Sharingan."

No, they're not the ultimate evolution of Sharingan. It should be Rinnegan. But, yeah, continue. Seimei thought impudently, but he stayed silent, carefully listening to what Tobirama had to say.

And Tobirama kept explaining, "When someone awakens Mangekyo Sharingan, they also awaken two unique, sometimes, even reality-breaking, ocular techniques. One in each eye."

"Amaterasu, Tsukuyomi, Free Elemental Manipulation, Mind Control, Absolute Immunity to Genjutsu, Future Vision, Simulation, Ninjutsu Enhancements, Absolute Healing, Space-time Techniques—Mangekyo Sharingan can give birth to one absurd technique after another."

"Then, they have the ultimate form of Yin Release. The ultimate power that every Mangekyo Sharingan user possesses: Susanoo."

"I won't go into detail about it now."

Tobirama took a deep breath before continuing, "However, this power is also like a curse."

"The more you use the powers of Mangekyo Sharingan, the more vision you lose."

"Each use of Mangekyo Sharingan techniques will lead to permanent loss of ocular power. Although the users can replenish their lost ocular power, the process is so slow that it's almost negligible."

"Eventually, this will lead to permanent blindness."

Then, Tobirama turned to look at Seimei with a serious expression.

He said, "With your talent, you will awaken Mangekyo Sharingan one day."

"Although I want to tell you not to use their ocular techniques, life is unpredictable."

"Of course, if you can awaken Eternal Mangekyo Sharingan like Madara, then the problem of losing vision won't trouble you at all."

"But you don't have any close blood relatives here. So, awakening Eternal Mangekyo Sharingan is impossible for you."

Actually, I feel like I will directly awaken the Eternal Mangekyo Sharingan because of my Otsutsuki bloodline. If that's not possible, I still have the proficiency system to evolve my Mangekyo Sharingan into its eternal form.

Seimei thought silently as he kept his focus on Tobirama.

Tobirama softened his voice and said, "You're my son. And I don't want to see my son go blind."

"That's why I began my research to find a way to solve the blindness problem of overusing Mangekyo Sharingan."

"And after nearly five years of research, I have finally found a couple of solutions."

Then, Tobirama turned his head to the vibrant green potions.

"I still need to run several trials. But within six months, I will perfect this potion. It will be a kind of eye drop. Eye drops that will replenish the lost ocular power and solve the blindness curse of Mangekyo Sharingan once and for all."

--------------------------------------------------------------

A/N: If you like my story and want to read ahead, you can check out my P@treon page and read up to 20+ Advanced chapters!

patreon.com/Seigan

You can also help me by sharing the story around. Thank you for reading!