Allow me to tell you about the Great Lolicon Dream™. No, not the wet, lucid ones I have of lolis every other night, but rather, one of the many tenets prescribed in the Lolicon's Creed, which is imbued into each and every single one of my kind when we take on the oath of brethrenhood. While lolis are everything that is right with the world, their existence on this material plane are but a temporary one, as the fleeting charm associated with pre-pubescence will eventually dissipate with age, forcing us to move from loli to another. That said, there is one exception to this rule, which only the most blessed of my brethren are able to achieve; Leaving an impression so strong on a loli that she pre-surrenders her chastity through a nuptial vow, sealed with the phrase "I will become onii-chan's bride when I grow up." The very epitome of winning at life if you ask me
Nadeko's opening theme reflects that very notion, and after that brief conversation with Araragi prior to the cleansing ritual, it is beyond any doubt that Nadeko made a vow of such a nature, only to be nonchalantly acknowledged by Koyomi, who, at that point in time, had not yet embraced the teachings. Sadly, much like his vampirism, Koyomi's lolicon tendencies were somewhat suppressed, preventing him from ever cashing in on that promise.
Nadeko herself becomes aware of this unrequited love, and the pain of knowing that, I can imagine, is greater than being constricted by two snake demons. Nadeko, truly, had a hard life Being the good girl that she is however, Nadeko took it all in stride, contented with the reunion with her onii-chan. How I wish that I could embrace Nadeko and become the big brother figure that she had always desired Before anyone refutes my statement, let it be known that while every one else is fair game, true lolicons again, live by the tenets prescribed in the doctrine, another one of which is to never, under any circumstance, defile the imouto character. If only people would stop lumping us together with your garden variety child sex offenders, one may realize that we are an honourable lot with principles.