When I was seven, my older brother came down with an awful case of teenage rebellion. After the sun went down, Itachi gathered up his blades and his chakra and sent the whole clan to sleep, forever. The thirteen-year-old seemed awfully proud of this achievemen; I arrived home late to a movie night I would never forget. Itachi stuck me in a genjutsu so I could fully appreciate his holocaust, in as much horrifying detail as the senses can provide. I don't know how many times he made me live through it. After a couple hundred times it all just blurred together into one endless nightmare.
When I returned to consciousness, Itachi was long gone. It was an amazingly powerful genjutsu. Perhaps, it was just a bit too powerful for him to handle back then. In the days following that blood-drenched evening, I discovered that my brother had also left me with an array of strange memories and habits from a strange world. It was a wonderful world. I often found myself sorely missing the amenities of that world—the seemingly inexhaustible well of knowledge known as the Internet, the ability to travel and relocate across entire continents and oceans, plentiful food in great variety...Was it all something Itachi had cooked up to further satiate his sadistic appetite? Whatever the nature of the memories, they intruded upon me day and night, a constant reminder of my solitude and impotence.
One morning, not long after that night, I looked in the mirror, and saw two Sharingan staring back at me.
The Uchiha liked to claim that the Sharingan is a testament to love. Outsiders liked to whisper that the eyes are a manifestation of curses, madness, or hatred. In reality, the Sharingan develops under certain physiological conditions symptomatic of extremely intense emotions. Usually, such strong emotions are triggered by specific external events, which often involved loved ones, but they can also be caused by factors entirely internal to oneself—a mental disorder, for instance. This was my hypothesis, which I have since confirmed.
After I had formulated my hypothesis, I wasn't sure whether to laugh or cry, so I sat down with a glass of water and thought a little about it. Crying, I decided, was infantile, loser behavior, so I laughed, and laughed hard. I suppose wouldn't have looked strange in a loony bin.
Now, philosophizing about big ideas like sanity, memory, and personal identity is the kind of thing nice people do in comfortable circumstances. They imagine that thinking about big ideas makes them smart, like saying big words. Now, I wasn't exactly a nice person, and my circumstances were far from comfortable, but all of a sudden I had something of an epiphany: clearly, there was one person I could easily blame for all my troubles. It didn't take much philosophizing for me to decide that I was in a great hurry to wreak bloody vengeance on my dear brother.
I now had an end in mind, but my means were ludicrously insufficient. Itachi was clearly capable of single-handedly annihilating dozens of powerful warriors, for that was exactly what my clan had been. He could have killed me a thousand times over and not received so much as a scratch; the most I could have hoped for was that he would bust a gut while cackling at my anguish. My ignorance of the world was obvious and appalling, so, good citizen as I was, I took an indefinite leave of bereavement. But I've never been much of a mourner, so instead I scoured the library, and then every bookshop I could find. The Transformation Jutsu was wonderfully useful for bypassing age restrictions, which were plenty—perversity and degeneration were shockingly rampant and profitable in those days. I was willing to leave no stone unturned, but despite my industry, I was only human, which inconvenient physical limitations in abundance, a fact which I found most intolerable. Thankfully, before I reached the brink of despair, in a stroke of good fortune, I discovered a book that revolutionized my process.
I encountered the volume in a very adult establishment. It was an illustrated guide to obscene uses of ninjutsu. I will not disclose the exact name of this book, since I do not wish to direct you, my dear reader, to such an unsavory publication. Nevertheless, intrigued, I activated my Sharingan behind my aviators, and in a matter of minutes committed the whole book to memory; as sole heir of the dozens of dead Uchiha, I had plenty of money, but I wasn't about to patronize filth. I tipped the clerk on the way out and briskly made my way home, not neglecting to change my appearance at an opportune moment.
I laid down in my bed—formerly Itachi's bed. Of course, I had burned the sheets and the mattress. The rest of the room had borne almost no trace of Itachi; for as long as I could remember, my brother was rarely home, always the busy shinobi boy, very busy spying and killing. Compared to my old chamber, this room was positioned farther from the living room, the floor of which was forever stained with my parents' blood.
I lay down, closed my eyes, and perused my fresh memories. The dirty book included information on many useful techniques—chakra strings, chakra blocking methods, various genjutsu, etc. There was one ninjutsu, however, which made the rest seem almost tame: the Shadow Clone Jutsu.
The book made it clear, in a memorably disgusting passage, that Shadow Clones can record sensations that are transmitted back to the original upon dispelling. The momentous implications of that struck me immediately: Shadow Clones are essentially capable of producing, or at least reproducing, time itself, a feat which was almost inconceivable to me before I learned of such a jutsu. If I were to spend an entire day with one Shadow Clone running around, doing his own thing, at the end of the day, I would have lived two days instead of one, even though for everyone else, as well as for my physical body, only one day would have passed. Combining Shadow Clones with the use of my Sharingan, I could quickly amass a ridiculous amount of knowledge within a reasonably short period of time, at virtually no cost to myself.
That was my naive delusion. In reality, I was barely able to sustain one Shadow Clone for a few seconds before I lost consciousness entirely. I woke up in a hospital bed, where I endured a long-winded tirade from the Hokage about how very close I had come to death. Ironically, I was rather relieved: it was clear that the ever-benevolent state at least placed considerable value on my continued physical wellbeing, a fact which boded well for my survival and eventual revenge.
Of course, I went straight back to my reckless ways. My second attempt at the Shadow Clone Jutsu was much more successful; I was able to dispel the clone within two seconds of its creation. It only left me utterly exhausted, nauseous, and nursing a violent headache. But as we all know, insane people tend to do the same thing over and over again, so the next day, and the days after that, I did the same thing over and over again, and over the weeks, I was able to extend my endurance to three seconds, then five seconds, then eight, and so on. My endurance grew exponentially, for reasons that I would not discover until much later.
After half a year, I had gained enough endurance and mastery to create up to the jutsu's maximum of 2000 Shadow Clones. It was abundantly clear to me, however, that if I actually attempted to exploit the full cognitive capacities of all those clones, the mental strain would probably cause me to enter a coma, or perhaps even kill me outright. After all my hard work, I again had to start from scratch. That infuriated me. I was also suffering the insipid hell known as the Academy, to which I had been forced to return. In response to these grievous injustices, my volatile emotions triggered further development of my Sharingan, which were soon replete with three tomoe each. This was really a curse in disguise: the evolved Sharingan irreversibly acquires a far higher frame rate and resolution. While useful in combat, these characteristics meant that an eidetic memory of the same length now entailed a far greater mental load, and thus made my Shadow Clone scheme all the less realizable.
All these setbacks would surely have disheartened any reasonable person, but I had such a glorious, indelible vision of what I would obtain through the success of my unlikely enterprise; why, I could practically see eternity in the hour and infinity in the palm of my hand! So I persisted with a tenacity and foolhardiness befitting of the Uchihas' nasty reputation; in a bid to improve my endurance, I resolved to keep my Sharingan active throughout the day; it was excruciating: not only did daily exhaustion make my eyeballs feel like they were being violently ripped from their sockets, I was occasionally tempted to gouge them out myself, despairing of the wretched and idiotic behavior I was frequently exposed to within the Academy, and which my eyes readily captured with horrible clarity and permanence. I wore shades so as not to alarm my duller associates when I shed literal tears of blood; I'm sure that the brighter and nosier ones were not fooled. Certainly, the ever-benevolent and watchful state of Konoha knew all about the development of my eyes, and must have been very well pleased, the way a farmer would be pleased to own a fat pig.
At long last, after another two years of pure torture, I was finally able to maintain two Shadow Clones throughout the day while utilizing their mental abilities to the utmost. I was on the fast track to becoming a savant of a magnitude that the world had never seen, and things were only getting better from there. Again, my capacity was growing exponentially, and by the time I graduated from the Academy at age twelve, summa cum laude, of course, my mental age, not counting my memories of another world, was somewhere around fifty years. Compound forty or so of those years by the aid of the Sharingan, and you have a till then unprecedented degree of learning.
I had a rather high opinion of myself. Why would I not? I had a systematic and comprehensive understanding of every type of ninjutsu under the sun, and had come up with a few of my own. I had diverse memories of a highly advanced civilization, which gave me all sorts of extraordinary ideas, and I had a truly formidable amount of chakra at my disposal. I was almost as confident in my abilities as a moron is in his intellect.