DISCLAIMER: I do not own Baka to Test.
From the very beginning, I have always watched you. Always have I been together with you; through the hard times, through the sad times, and, best of all, through the happy times, my dearest twin. I have never left you, and you have never left me... and because of that, my life is one full of utter joy.
Over these seventeen years, I have stood by your side, comforting and being comforted; protecting and being protected; loving and being loved. We've shared many moments together, precious moments that I will never forget even when my hair turns white. We've laughed together under the sky too many times to count, and have cried together under that same sky while being embraced in each other's arms.
Over the course of time, however, certain feelings arose within me. These feelings weren't what a sibling should feel; feelings that stirred my heart and made me... fall in love with you, my twin. I'm not able to look at you in the same way as I did years ago, nor am I able to think of you in that same way. My thoughts of you are ones of a lover, and those thoughts have not changed for more than five years.
I know not of what this love will come to in the end, but I shall always stand by your side. Even if you only think of me as a sibling, I shall always love you with all of my heart until the very end. And, one day, I hope that you will return these feelings of mine.
Until then, I will always be loving you.