Hunter X Hunter: Twins in the Mirror

I think he and I are like two sides divided by the surface of a mirror. Though we are twins and look very much alike, we are also very different. Our faces and figures are the same, as if stamped from a single mold, like mirror images, almost perfectly capable of taking each other's place. But that's only an illusion. Just as when I hold out my left hand, the person in the mirror will always hold out his right. We can never take each other's place. In other words... Neither of us can ever be replaced.