The clue said somehting about Snow White, yeah?
And the answer is staring us right in the face.
What theory did we dismiss? That WE ARE The Black Parade.
There's a Magic Mirror in Snow White. We look in the mirror, what do we see? A very crazed MCR Fan. A member of The Black Parade.
EDIT: sanityadoration was the first person to bring the theory that we are TBP to my attention, so- kudos :)
*think- the slogan on the shirts, and the website? "WE ARE THE BLACK PARADE"*