A/N: For my friend Helen, who gave me this prompt as a quote: "When you grow older, you don't stop pulling the wings off butterflies. You just find better reasons to do it."
Killing should be nothing strange to a Shinobi. The life demands they steel themselves against the bloodshed and continue on as if nothing happened at all. Another person's agony as they crumple to the ground like a broken toy cannot be permitted to work under their dutiful resolves. The spilled blood continues to flow like a never-ending current, and shinobi invariably learn over time to prevent it from pulling them in.
Itachi was still young when the current first started to lap around his ankles. His father beat apathy into him with a lashing tongue and endless training. Older Uchihas never failed to tell him detailed stories of their own battle encounters. Talk of the deadly current even had a way of punctuating their dinner conversations at odd moments.
The younger Itachi never saw reason for the endless training and hours of the torment that was the regular conversation around the Uchiha compound. What he did understand is that emotions made him weak- better to kill and get it over with than to dwell upon the life about to be extinguished, its being tossed into the ever-flowing river at his feet.
Even when he first entered the academy, Itachi's resolve was deadly indeed. He would practice and fine tune his sharingan in private, using it to snuff out the life of little squirrels in the training grounds, slicing whatever target he saw most convenient into ribbons with his shuriken and throwing knives. Itachi didn't care. Death was nothing, lingering over it would only slow his progression. Better to move past it without blinking then dwell on the inevitable.
His teachers and elders alike praised the traits that Itachi's fellow students feared. They regarded him as a prodigy who would one day rise to greatness. Itachi didn't care any more than he cared about the lives of the small animals he took in his training
No one noticed when Itachi's little pet kitten dissapeared. Sure, they asked him about it, but how could a boy of 10 kill his own pet? They ignored the incident. After all, Itachi was a good ninja, and no one was around to witness hisperverse pleasure as he squeezed the life out of the small animal in order to test his ability to kill.
No one suspected the day his cousin added to the flowing entity starting to burble around Itachi's knees. All agreed- the boy was found floating in the water, he probably drowned. Yes- no one suspected that his own cousin sacrificed the life of his best friend to progress his own skills.
The family would regret the oversight when a few nights later, Itachi's mangeko sharingan obliterated the entire Uchiha clan save one member. He laughed as he walked away from the massacre, blood dripping from his katana, the red commas still glowing in his eyes.
Itachi reveled in having finally found a purpose in his life. He desired power- to become a legend, even among missing nins. He would find a way to subjugate other ninjas until he alone ruled them all. The killing, of course, would not be enough. He would wait until the last remaining member grew as strong as he before his final strike. That would be his test.
If he can defeat his brother, Itachi will finally be satisfied in being one of the strongest and most powerful ninja the world has ever known. After all…power is the reason for everything.