Turning a corner in the silent streets, Itachi made his way out of the Uchiha Clan's enclave. He passed the gates bearing his family crest, sparing a brief glance at the corpses of the guards. He noted critically that his kunai had severed Maruko's spine an inch lower than he had been aiming. She was faster than I thought. Not nearly fast enough, but faster than I expected.
He could still hear the wails of his heartbroken brother echoing from behind him, filling the air with his pitiful pain. Itachi knew why his brother was screaming, he just didn't understand it. Why value the life of those too weak to stand on their own, too weak to protect their lives? Anyone who died at the hand of another was too weak to be worried over. Except Shisui. Shisui hadn't been too weak to care for, not when Itachi had to care for him. Now that he had what he wanted there was no reason to care any longer. He let himself drift back to that day as he worked his way out of Konoha.
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He and Shisui stood by the river, talking of unimportant things; Shisui talking and Itachi feigning an appropriately mild interest. Itachi had decided long since that Shisui would be the one to die, the one sacrificed to attain a greater power.
The catch was that Shisui had to matter to him, to be important to him…in a good way, like a friend. The days were long gone when Itachi felt like that about anyone. Many people mattered to him but in a different manner. They were a nuisance; they interrupted his training and objected to his actions. The pests mattered, but he didn't care about them, he cared about avoiding their irritating restrictions and questions. Therein lay the problem, he needed to care again. He'd managed it. Shisui had become important to him, a part of his life, but now it was time to trade Shisui's life and importance, to better his own life and his own importance.
Itachi casually moved closer to Shisui as he talked, approaching from behind. His eyes went from black to red as he activated his Sharingan. Shadows of Shisui's future movements appeared along side his body, showing exactly where the man standing on the river bank would be over the next few seconds. Itachi poured his chakra into the Sharingan, focusing it on the pinwheel pattern in each eye. This was one of the greatest challenges in obtaining this new power, fining flows of chakra to collect and focus in an area that small required great skill. Itachi had that skill.
When Itachi was sure that he had accumulated enough chakra behind his eyes, he struck. His hands quickly landing four soft but surgically precise blows to Shisui's neck and back, hitting points carefully chosen to immobilize the target, but to leave no lasting mark. Shisui collapsed onto the river bank quietly groaning as the flow of his own chakra was forcefully diverted, boring countless invisible holes through his internal organs.
Painfully he looked up at Itachi, realizing that he had no choice but to fight back, and no chance to win. Activating his own Sharingan with the last of the chakra under his control Shisui could see the beginnings of Itachi's technique, but he did not understand what it was designed to do. What Dojustu1 requires that much chakra? Itachi moved forward and easily lifted the weakly struggling form in front of him. He calmly walked waist-deep into the river and forced Shisui below the surface. Shisui thrashed feebly, his muscles confused by the surging chakra running amok in his body, and managed to turn to face Itachi. Itachi ensured that Shisui's head was under water and little else…he didn't care as long as Shisui died by his own hand, but this he could claim was a natural death and thereby avoid some of the pestering that would inevitably follow.
Shisui's mind fogged as he lost oxygen. He could see his friend's face, the cold eyes watching as he died. As his vision faded, the last he saw of his friend was his eyes. The veins swelled, and the patterns of the Sharingan swam, flowing, changing and then… darkness.
Itachi felt life leave Shisui, and felt the chakra in his eyes surge, forcing itself into webs and flows that Itachi couldn't control. The scrolls had told of this, but Itachi wasn't prepared for it, his own chakra being pulled and distorted, it was unsettling. It was over quickly. Itachi felt the instinctive technique complete itself, the transformation finished.
He could see! In astounding detail he could see what was around him, where it would be, where it had been. It was as large a difference as moving from an incomplete form of the Sharingan to the triple-piped version that most Uchiha referred to as the complete form. Complete form? Hmph…this is the true complete form, none of them understand the power behind these eyes…none of them knows the truth. He knew that improved sight was the least of what he could do with these new eyes. They were called the Mangekyou Sharingan…Kaleidoscope Sharingan, they possessed the power to make people see what he wanted them to see, feel what he wanted them to feel, but he would have to work to master that technique. The scrolls spoke of the immense chakra use and control required to perform a true Tsukuyomi technique.
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Well he had mastered the Tsukuyomi, as he had proven tonight. Many had fallen before it, and it had proved most useful in provoking his brother. Itachi greatly hoped that the little one would have the sense to gain the Mangekyou for himself, Itachi wanted a challenge from the boy, he showed some promise, and with a newly awakened hatred driving him…he could be a very interesting challenge indeed.