The Secret of the Uchiha Eyes
"Tianqi, I'm sorry, you must have seen this funny!"
After driving away Ōtsutsuki Mandala and Karura Ōtsutsuki, Indra awkwardly nodded to Tianqi.
"It's alright!" Tianqi shook his head slightly and paused for a moment before asking, "There's something I've never understood about Indra, and I'd like to ask you about it. I wonder if you could..."
However, before Tianqi could finish speaking, Indra waved his hand magnanimously and said, "Tianqi, you don't need to be so polite. Now that you've come to my place, you're my Indra and brother. Just say whatever you want to say, and I'll tell you everything I know!"
It's clear that Indra wasn't a truly evil person. He treated his friends quite well, and there's a reason why Indra could raise a powerful army of a thousand men. Perhaps he did dislike Asura and Ninja Sect members, but he treated his subordinates exceptionally well, like family.
"Since that's the case, I won't stand on ceremony with you, Indra. I'd like to ask, how did you evolve the Mangekyō Sharingan into the Eternal Mangekyo Sharingan?"
This is the question Tianqi has always wanted to ask. As far as he knows, the Eternal Mangekyo requires the transplantation of the eyes of one's own brother to evolve successfully. However, Asura, who is Indra's brother, does not have the Sharingan. So how did Indra's Sharingan evolve into the Eternal Mangekyo Sharingan? This is a mystery.
"Hahaha, I thought you wanted to ask something else, but it turns out it's this!" Indra laughed heartily, his black pupils instantly turning red, and the pentagram Eternal Mangekyo appeared in an instant.
However, Indra continued, "My Sharingan awakened when I was a child, in order to protect Asura. As I grew older and stronger, my eyes kept changing, and my ocular power grew stronger every day. When I was fifteen, because that old man chose Asura and rejected me, after sacrificing two of my most loyal followers, I awakened the Mangekyō Sharingan and completely betrayed Ninja Sect. In the battle with Asura, I even awakened the Eternal Mangekyo Sharingan, which even that old man never possessed. Although I hate to admit it, it is indeed the truth. My power was inherited from that old man!"
"I see!" Tianqi nodded. Although it was just a simple answer, Tianqi roughly understood the truth of the matter through it.
According to Tianqi's conjecture, this should involve bloodline concentration and Yin Power. As the Third Hokage of the Ōtsutsuki, Indra's bloodline power must be extremely strong. As he grew older, the power of his bloodline was fully activated, and the Yin Power in his body continued to grow, which is why he now has the Eternal Mangekyo Sharingan.
In fact, Tianqi had always had questions about the practice of transplanting his brother's eyes. How could simply changing a pair of eyes lead to evolution? There were many things that couldn't be explained. However, after learning about Indra's precedent, Tianqi finally understood.
Because the Uchiha clan members of later generations had a diluted bloodline, the Yin Power in their individual eyes was not enough to propel them to the Eternal Mangekyo. Therefore, they needed the Yin Power of another pair of Mangekyo to combine and complete the evolution. As for why they used the eyes of their own brothers, it was probably because the Yin Power in the eyes of brothers was more compatible and would not cause any rejection.
As for the scene showing Indra evolving a Nine-Tomoe Rinnegan, it's easy to explain. The original method for evolving the Rinnegan is a perfect combination of the Sage's Eye and the Sage Body. As Ōtsutsuki Hagoromo's son, Indra must have inherited part of the Sage Body. After intense stimulation and development, it's normal for him to be able to awaken a single Rinnegan.
As for why Sasuke Uchiha in later generations was also able to awaken the Rinnegan, it was because Ōtsutsuki Hagoromo forcibly Yin Power. It was completely different from the Rinnegan that Indra evolved through his own Yin Power and a partial Yang Power. Compared to Indra, Sasuke Uchiha was just a half-baked one.
Having figured out the reasons, Tianqi secretly regretted not passing on his best genes to his offspring. When Tsunade had Sen'u, Tianqi hadn't yet acquired the Rinnegan; he only possessed the Sage Body. It's estimated that Sen'u's peak in this life would only be the Eternal Mangekyo Sharingan, and as for the Rinnegan, it's probably impossible for him ever to have it.
Just then, Karura Ōtsutsuki had left, returned. Upon seeing her, Indra's previously improved expression darkened again.
"Why are you back again? Didn't I tell you not to mention that matter again? I'm determined to defeat Asura!" Indra snorted and turned his head away.
Seeing that Indra was just a stubborn, unyielding rock, Karura was quite helpless. However, when he recalled that the person in the living room had been chatting and laughing with Indra when he came over, Karura's eyes lit up and he suddenly had an idea.
She jogged up to Tianqi, gave a slight bow, and then asked softly, "Excuse me, are you the one my second brother Asura mentioned, the one who doesn't belong to the Ōtsutsuki clan but possesses the Sharingan?"
"Uh... if there's no one else, then it must be me!" Looking at the face of Hinata Hyuga, yet not Hinata Hyuga, Tianqi felt very strange. This resemblance yet difference always made him feel uneasy.
The two then started chatting. Karura and Tianqi became more and more interested in the conversation, and eventually even sat down next to Tianqi. Karura kept asking all sorts of questions and occasionally burst into laughter, which made Indra quite angry, and black lines kept appearing on his forehead.
"You two, stop this already! I'm the master here, what do you mean by ignoring me!" Indra glared at Karura and Tianqi, clearly displeased.
Because Tianqi was having a pleasant conversation with Karura, he didn't see Indra's expression. After all, Indra was a goddess from the Hokage anime. Although she only looked like her, she was undoubtedly a goddess. Moreover, the noble aura that Karura possessed was something Hinata Hyuga didn't have. Being able to chat with such a noble goddess was very attractive to Tianqi, who used to be a loser.
However, after hearing Indra's displeased roar, the two stopped talking.
"Tell me Karura, what brings you back now?"
Indra glared at the 27-year-old girl, his eyes filled with displeasure. Clearly, he was very unhappy that she and Tianqi had been chatting and had forgotten about him, the person in charge. No one had ever been able to ignore his existence since he was a child, and these two dared to forget him. It was simply outrageous!