In the end, despite his best efforts, he failed. To complete his plan, to find redemption; in both cases, he failed, and for that he lost his life. For that, he ended up here, in the endless expanse of gray. On either horizon, there seemed to be two different suns; one white, one black.
Turning his back on the white-hued sun, Obito made his way towards the sun composed of nothing but darkness. He wondered if spiritual hell would be easier to exist within, than the one he left behind.
"That's it?" a voice, so familiar yet one that hadn't been heard in over a decade, turned its rebuking tones towards his ears. "You're not going to even give the white gate(1) a try? So much for your once boundless optimism."
He didn't even pause in his stride towards the blackness of hell as he replied. "That optimism died years ago, when I found myself in hell on earth."
The sound of footsteps began to tap their rhythmic beat behind him as he walked. "You gave up on the world simply because the girl you liked died?" the voice asked derisively.
"No," he said with a tired voice, "it wasn't simply because she died. It was that my only other good friend, the boy I had entrusted her safety to, wasn't able to stop the slide into becoming trash after all." It was at this point he finally stopped and turned towards the one he had been talking to. "And when comrades kill comrades, when the world is filled with nothing but lies, what other thing can you call this thing we refer to as living but hell, Mikoto-nee-san?!"
Mikoto Uchiha closed her eyes for a small moment, digesting the words of the man standing opposite her; the man who had once been her hyperactive little brother. Even now, with years of watching him as much as a spirit could, it was hard to believe he had grown into the man would start the Fourth Great Ninja War and bring about the revival of the One Eyed God(2). She opened her eyes, the red of the sharingan blazing forth in its crimson light. It might be hard to believe, but it was the truth.
"Sometimes, little brother," Mikoto said gently, yet with conviction, "the lies can become the treasured truth that turns that hell into something far more bearable. Or did you forget those words I said to you all those years ago?"
Obito closed his eyes as he shook his head, chuckling darkly to himself. "Itachi may have gotten his loyalty to Konoha from his father, but he received his manipulative nature from you, it seems." He opened his eyes, his face once more devoid of any expression, save through his sharingan. "I believe they were 'I acted as the older sister you desired in order for you to grow into the capacity I saw at the moment of your birth'. I figured you were lying at the time, and thought my feelings about it were confirmed when I saw you after my 'death' at the Kannabi Bridge. Are you saying that was the truth? How very like you, Mikoto."
"What I said that day, was the truth, little brother," Mikoto said sadly, her eyes wandering towards the ground. "But like everything in this world of the shinobi, it's much more complicated than a simple truth would have you believe. Did you know, that on the day of your birth, you awakened your Sharingan, if only briefly?" Obito's eyes widened at this, but Mikoto didn't notice as she continued. "You did it in front of both Fugaku and his father, when our father presented you to the clan head, as was custom at the time."
Mikoto smirked as she recalled the memory. "Needless to say, your little stunt put the whole clan in an uproar. To be able to do such a thing merely out of reflex, as opposed to achieving it through intense study and training, meant that your innate talent as an Uchiha shinobi would elevate you over much of the ninja world. However, the power of the sharingan is not the kind of thing that should be placed in the developing hands of a child, let alone an infant. So the clan contracted a few of the remaining Uzumaki clan to help in the process of sealing your Sharingan away until you were to make chuunin."
"Why that long?" Obito began to ask, before his facial expression gave a sudden shift in response to something clicking in the confines of his mind and he held up a hand to forestall an explanation. "It was to prevent my reliance on the sharingan at the expense of my other abilities, wasn't it?"
His elder sister nodded her head in ascent. "Yes, and no, little brother. While that can be a problem, the Uchiha clan always had methods of training that out of its more headstrong members. No, the reason why it was put off for so long was that your baseline sharingan, the one you showed us the day of your birth, had the same chakra intensity of a chuunin. In comparison, my sharingan, one of a jonin, had the baseline chakra intensity of an academy student at best, a child at worst. It's detrimental not only to the shinobi's growth, but to the eyes' development as well for them to attempt to use their ocular powers before chakra control is on par with the baseline strength."
"Minato knew about this through Kushina, didn't he? That was why he was chosen as my sensei," mused Obito aloud.
"Yes," Mikoto replied, "Minato knew about it. He was also…uniquely talented in imparting the skills and teachings that made up the qualities of a superb shinobi, so it was deemed that being a member of his squad would be the best for you in the long run." Mikoto smiled at the recollection of a long-treasured memory, "Even if, in the short term, you thought it was the most aggravating thing ever to be on the same squad as the Hatake boy."
"You said," began Obito as he ignored her comment on his long-forgotten 'rivalry' with Kakashi, "that 'Sometimes the lies can become the treasured truth'. What did you mean by that?"
"When I first heard that mom was pregnant with you, I wasn't exactly thrilled about the prospect." She smiled wistfully as she remembered her younger self, "I had just turned 12 a couple of months before, and was already busy with the upcoming chuunin examinations. What teenage girl wants to be saddled with a baby underfoot? But the next year, in the middle of February, you were born and showed the world the potential of your sharingan. So I made a promise to myself: I would be the perfect elder sister, so that you could grow up to be the perfect Uchiha, my reservations about being an elder sister with such an age gap between us notwithstanding.
"But," Mikoto continued with water misting over her eyes, "after a couple of years I wasn't pretending to be the kind, concerned, nagging older sister you needed. I realized that I truly did want to be that for you, not because of your potential, but due to you being my dorky little brother who helped little old ladies with their groceries."
"Thank you," Obito said unexpectedly, and judging from the look on his face, it wasn't just Mikoto who was surprised that he spoke those words, "for giving me that explanation." He paused for a moment, before turning his back towards the woman he had once called 'nee-chan'. "In repayment, if there's anything you want to know about why I helped Itachi that time, or why I released the-"
"No," Mikoto interrupted him, "I don't want to know about that. I was just curious as to why you lied to Sasuke."
"About my being Madara?"
"No, about who was really behind the attempted Uchiha coup d'état."
This brought about a small pause from Obito, but it didn't last long as he replied, "You had turned yourself into the image of a gentle woman for the sake of your sons. I was already shattering his reality, it wouldn't have done any good to shatter the last hopeful illusion he held about the reality of the past. Not even Itachi knew of you being behind the majority of the planning, even until the end."
"Thank you, Obito, for that."
"Hn," he huffed in amusement. "Of all the things that would be said before I march into hell, and I get a 'thank you for lying to my son'? Uchiha are Uchiha even after death, no?"
"Stay safe, little brother," Mikoto said to the empty air, before turning away from the black gate and heading towards the white sun once more.
END
AN: 1 The "white gate" is the entrance to the 'heaven' side of the Pure World. From a distance it looks like a white sun amongst the endless gray that is the 'purgatory' part of the afterlife. It is here (in the gray plane) where memories that are gained during one's existence in the Pure World are left behind when one is called to the Impure World due to resurrection (hence why Edo Tensei zombies have no memories of an afterlife)
2 The One Eyed God, Datara, Deidarabocchi, Ten-Tails. Origin of chakra and the progenitor of the current world.