ZI: "As with many details in the chronology of Zelda, the true nature of Zelda's power has long been a hotly debated topic among Zelda theorists. For years it seemed that rather than explaining Zelda's powers each new game only clouded the issue more. New, vague references to Zelda's power appear in multiple games with little explaining how or even if this power relates to any of the previous ones. If you've been following the Secrets Of Skyward Sword series here at Zelda Informer, you've probably guessed what I'm going to say next. Skyward Sword once again holds the clues to this mystery in Hylian history. Coupled with some new information from the Hyrule Historia book, the secrets of Zelda's powers will finally be uncovered.
If you look at each Zelda title you get a steady stream of information about the powers of Zelda throughout the series. To get the full picture, you have to look at everything we know from all the games in light of what Skyward Sword has to say on the issue."