Maybe it's just me. But I've noticed that everyone thinks that the female character in the picture could be a form of a "Zora" or even Zelda herself.
Well maybe I'm nuts but take this into consideration.

There's no sword in his hands.
Now I know that this has already been noticed.
However, look again at the girl next to him, upside down.
Her head/cape kind of looks like the bottom of the master sword while her skin is an odd gray-like color. Kind of like the blade. Also notice the jewel on her chest around the same area the master sword has one on the holder.
Is it possible the master sword plays a more significant role (as the King [boat] in Wind Waker), also noting that in the last few games the master sword has been referred to as a more "living" object in the series. Maybe it's just me but eh, what do you think?