Who does protect you, shadow or light? Or both?

Midna: "Light and shadow can't mix, as we all know. But… Never forget that there's another world bound to this one."
Zelda: "Shadow and Light are two sides of the same coin, one cannot exist without the other. I know the reason the goddesses left the Mirror of Twilight in this world. They left it because it was their design that we should meet."