The idea for this little "story" comes from chapters 385 and 386 of the Naruto manga. Read at your own risk. I do apologize if Itachi seems a little OOC, but I haven't read a lot of the manga with him in it, and articles I found did not give much information beyond basics.
Disclaimer: Just write fanfiction about, don't own.
Oh, sons of earth! attempt ye still to rise
By mountains pil'd on mountains to the skies?
Heav'n still with laughter the vain toil surveys,
and buries madmen in the heaps they raise.
Alexander Pope, "Essay on Man"
None so blind as those that will not see.
Matthew Henry, "Commentaries"
Foolish little brother for truly believing I cared about you. The only thing you ever were to me was a means to an end
"If you can awaken the Mangekyou Sharingan, then there will be three people who can use it, including myself." (1)
You believed I gave you that piece of information to help you destroy myself and my accomplice in retaliation for the death of the clan. Oh, very far from it. I will admit to mild surprise that you figured out I had not murdered the clan alone, but that made your reaction to my revelations all the sweeter.
Uchiha Madara was my true sensei, not those pathetic fools who teach at the academy or the fools of the clan. He noticed me as a small child, noted my potential, and molded it. I learned everything from him. Genius they called, yet he created the image. Upon learning his true identity, I was amazed, and asked to hear his story. The information I received astounded me, I wanted what he had, and asked him how to obtain it.
"Start first, by building Sasuke's trust and obtaining his love and admiration. He will desire to be like you, striving to become as strong as the Genius of the Uchiha clan."
When I wasn't on missions as a regular shinobi and later as an ANBU, I followed that advice. Such a pathetic child, swallowing everything I gave you, the training, the stories of the clan. But slowly you did become stronger, trying to become just like me in order to impress our father. When I heard one day how you mastered our family's Katon jutsu in only one week, that was the true signal to destroy the clan. Another step was required though, before that was accomplished.
"Before inflaming your brother's drive to come after you even farther, you must obtain the Mangekyou Sharingan. You know the necessary step for obtaining it. Come to me the moment you acquire it and we will discuss our next actions."
Friendship is nothing compared to immortality. Shisui's death was so pathetically easy to accomplish. I cast a Genjutsu on him while he was walking to the clan meeting, making him believe the river was actually the land itself. He realized the trap seconds too late. Being deathly afraid of water, he could not swim, and drowned within moments as he panicked. Afterwards, Madara himself planted the suicide note he wrote after I gave him the information on Shisui.
"The final step requires waiting a few weeks, in order to calm suspicions. Give lip service as you kill all emotional ties to the clan. Suspicions will fade as you give no signs of being a killer, making the surprise all the more amusing."
True enough. Father was concerned, but unable to figure out the truth, could only instruct you in our clan jutsu and warn you to stop following me. Perhaps he meant to replace me with you as the heir. The fool did not realize you were watching me even closer, wondering what I was doing. As for mother, well you were her favorite. I rather enjoyed killing them. Madara slaughtered those who harbored the most suspicions against me.
"Do what is necessary to torment him. This will drive him to surpass you in order to avenge his family, but in reality will play into your hands. Be certain to give him the information of the scroll's location giving him the information concerning obtaining the Mangekyou. Go straight to Akatsuki from there. In time, you will receive the gift of immortality."
Everything went as planned that night. The Genjutsu images I showed you accomplished the goal of driving you to come after me. Since then, I have used the Mangekyou constantly, even knowing that blindness was the inevitable result of overuse. I hunted down the bijuu as ordered, simply biding my time, waiting for you to come before me. Through spies and contacts in Konoha, I learned how you buried yourself in training, how you graduated at the top of your class, and through an extreme stroke of luck, how you gained a best friend. It is a double edged sword, as obtaining the Kyuubi Jinchuuriki was my mission, but Madara knows a way to deal with that. Orochimaru angered me with his interference, however, I felt you would eventually become strong enough to overcome him, as he was growing weaker through his arrogance. He truly had no idea of the true secret of immortality. Learning of his death pleased me, for it meant you did not disappoint my expectations.
Now you stand in front of me, and I cannot deny you truly grew in skill and power, but I see your one weakness. You are like me, knowing the art of using people as long as they serve a purpose to you, discarding them once they are no longer necessary. Yet you cannot bring yourself to kill unnecessarily, the reason you do not have the Mangekyou.
Besides immortality, I have another ambition that I will accomplish: surpassing Madara. That will not take long. He is arrogant in many ways himself, beaten by the Shodaime after making a grab for power; gaining control of the Kyuubi, then losing it through the Yondaime's Shiki Fuujin Fuuinjutsu. He now sits within the shadows of Akatsuki, masquerading as a fool.
I have waited long enough. Mangekyou Sharingan or not, killing you will be most amusing. Let the final battle commence.
(1) As quoted from chapter 385. First quoted in chapter 225.
A/N: Hope as always that this was enjoyed by whoever reads it.