I saw you, how perfect you were, how everyone loved you...I wanted to be you. I wanted to be everything you were, but you didn't care. You didn't care about anything, about anyone. You didn't want their attention, their care, their love. You didn't want to hear me. I wanted to tell you, but I was too proud, too scared. So I never told you.
If I had told you back then, when we were children, how important you were to me...would it have changed how things turned out? If you'd known you were my reason for becoming better, my reason for living when no one wanted me to, would it have made a difference? If I'd spoken to you then, could we have been friends? Maybe you would've realized that there was more to life than avenging your clan, more to life than killing your brother.
If you'd known that, would you have stayed?
I can't say, because I never told you. Instead, we became rivals, enemies, and were forced to fight side by side despite it. You hated me because I 'slowed you down' I hated you because you were 'always better'. Somehow, somewhere along the line, we went from enemies to...something else. Comrades. Instead of fighting against each other, we fought alongside each other. After a while it no longer hurt to fight beside you; it became a contest, a way to become better.
Then you told me I was your best friend.
It didn't matter that everyone in Konoha loved you, it didn't matter that you only considered me 'friend' because I was a challenge, a worthy opponent. It didn't matter that I cared about you more than I should; you couldn't see it anyways.
We're both alone; you lost everyone and I never had anyone. Does it matter so much the differences when we're so alike?
Even without anyone else, we've still got each other. Does it matter why I would fight for you? I would; isn't that really all that matters?
'I can see', isn't it ironic that with those eyes of yours, you still couldn't see how much you meant to me? Even with those eyes, you still wouldn't see me for what I am, see what I'd do for you. You still couldn't see why I would keep fighting after you could kill me without an inkling of effort.
Or maybe you could.
Maybe you saw it, and hated it, and didn't want it to exist. So you ignored everything, and pretended I didn't feel how I did.
And when I became your best friend...I became a stepping-stone. I became a choice. Would you accept the new life you had open; as a person instead of a weapon? Or would you kill me, use me to get the power you needed to do what you'd sworn to do when you were still too young to know what it meant?
Maybe if I'd told you sooner, said it out loud so you couldn't pretend it wasn't there, then things would've changed. Maybe you wouldn't have to make that horrible choice; between your promise and your hope.