Naruto: Chakra System

Kakashi was genuinely surprised at Sakura's analytical question; if a Sharingan is transplanted in a deactivated state, and a non-Uchiha can't activate and deactivate it at will, then why is it always in an activated state rather than a deactivated one?

But Kakashi had the answer for it, as he remembered that same question was posed by Rin when she transplanted it. Even Obito initially gifted his left eye because he thought he was going to die and decided to gift his eye to Kakashi, who lost his left eye while protecting Rin from Iwa ninjas.

Obito's goal at that moment was to give Kakashi his vision back, as he had lost his eye, ensuring his friend had "both eyes" to protect himself and see the future. At that time, none of those three—Obito, Rin, and Kakashi—anticipated that the transplanted Sharingan would get activated once in Kakashi's eye socket.

The idea that the eye would retain its Dōjutsu state and constantly drain Kakashi's chakra was unforeseen, as there was no such known thing as a Sharingan or any Dōjutsu being transplanted into another ninja who didn't belong to the clan of that Dōjutsu. The fact that the Sharingan remained activated was a surprise to them all.

Kakashi then answered Sakura with the same theory Rin had told Kakashi at that time and said, "Sharingan is a Dōjutsu, not any normal eye, so even if deactivated, its power and specific pattern are still within it. And for me, a non-Uchiha, who can't activate and deactivate it at will, once it linked with my chakra network, the Sharingan remained activated by default of 'default on', to its powerful state, which is an activated state."

Sakura nodded after getting this answer, but Sasuke asked, "Can you show us your left sharingan eye?"

Kakashi stiffened at this request of Sasuke. Though it was no problem for him to show it to them, but he currently didn't have a Three-Tomoe Sharingan, but a Mangekyō Sharingan, which he wanted to hide from everyone for some time.

At least until he went out to try copying Haku's elemental Kekkei Genkai, Ice Release. Though Kakashi wasn't much sure if that could be possible, he thought it should be.

Because Sharingan can copy Elemental Ninjutsu, Genjutsu, and other techniques, plus now he has Mangekyō, making his copying ability much higher. And Ice Release, despite being called a bloodline limit, is actually an elemental Kekkei Genkai, created from merging two elemental natures—Water and Wind.

Kakashi, from his anime knowledge and his own thinking, only came to the conclusion that strictly pure genetic and unlearnable Kekkei Genkai are only Dōjutsu and physical/bodily Kekkei Genkai. Dōjutsu like Sharingan and Byakugan; bodily Kekkei Genkai like Kaguya Clan's bone manipulation called Shikotsumyaku and Jūgo's Sage Transformation.

These are the ones Kakashi believe should be called as the pure genetical Kekkei Genkai, which aside from these Clansmen can't awaken normally by anyone. Meanwhile, others like elemental Kekkei Genkai are both creatable and learnable, as shown and known that even Second Tsuchikage Mū had created a Kekkei Tōta, which is more difficult and rarer than Kekkei Genkai.

And later it was even taught to Ōnoki by him, who was his student, not from his family or son, and then there was even Third Kazekage who created Magnet Release Kekkai Genkai, and then taught it to Rasa, who also wasn't his son or belongs to his Clan; plus there was also Pakura from Sunagakure who created Scorch Release, this all makes Kakashi believe that if elemental Kekkai Genkai can be learned than maybe...

Kakashi thought that then maybe elemental Kekkei Genkai, despite being difficult, should at least be copied to some extent. And he wanted to try this on Haku's Demonic Mirroring Ice Crystals Jutsu in a few weeks.

Until then, he didn't want to show that he had Mangekyō Sharingan to anyone if possible, since he can't even transform it back to Three-Tomoe state; though he knew he couldn't hide it for all the time in the future. Kakashi shook his head and denied showing it, making a random but believable excuse for it.

He thought, 'Sasuke is this shocked at the revelations I made. Mangekyō Sharingan would be undigestible for Sasuke. That would be the biggest bomb on Sasuke's pride.'

With that thought, he sighed in relief, since Sasuke didn't pester about it further. Sasuke, after all, had high pride for his clan's Dōjutsu; the news that Kakashi evolved Sharingan was already hard to believe for him.

If Kakashi even told him that now what he had was Mangekyō Sharingan, which even in the Uchiha Clan only 0.1% can awaken and evolve, even those Uchiha who awakened Mangekyō can be count on fingers. If Sasuke knew, he would start to doubt the very existence of the Uchiha Clan's power and dōjutsu. Are they really that simple, then why do Uchiha Clansmen call it rare and boast about it?

Kakashi then comes back to main topic and said, "So, continue to train hard and then I will teach you some cool Ninjutsu, okay!"

Naruto was more happy with this. "Yes, Sensei," he said, "I will master Tree Walking and then Water Walking within this week, believe it! You just make sure you teach me a cool Jutsu!"

Kakashi and Sakura chuckled, while Sasuke also smiled a little, but hid it as fast as smile appeared on his lips. Kakashi nodded. "You are really motivated now, huh!" he said.

Naruto said aloud, "Yes, of course!"

Kakashi smiled mischievously once again under his mask. "And what if I tell you that I even planned to teach you and Sasuke an A-rank Ninjutsu later on as well?"

Naruto and Sasuke were stunned, looked at each other, and asked together stammering, "W-what, a-an A-rank N-ninjutsu? REALLY!?"

Kakashi chuckled; he could understand that Naruto would be surprised, as he had only one A-rank Ninjutsu, which was powerful, but he only learned it due to a mistake, it could be said, Mizuki being the reason. Otherwise, Naruto might never get his hands on the Scroll of Seals that easily, Hiruzen won't allow it.

But Kakashi was surprised that even Sasuke was excited hearing this, and thought, 'Yeah, now that I think about it, the Uchiha Clan has many Fire Release Ninjutsu, but none of them are A-rank, because Madara has taken many with him.'

Kakashi, thinking that, nodded in understanding. "Alright, I hope you take these as motivation and train hard further, and Sakura, you will be starting learning Medical Ninjutsu from tomorrow. And with this, let's call it a day. And as I promised, let's have Ramen before going to our ways."

Naruto jumped up in excitement and shouted, "Yeah, Ramen!" All the tiredness from capturing that annoying cat was already gone from his mind.

They then went to Ichiraku Ramen shop, had a delicious bowl of Ramen from Teuchi, which served by his daughter Ayame. After that, they said good night to Kakashi and went their own separate ways.