I didn't know we had those "check" tags, but I'm glad they exist. It's not confirmed that this is Hylia, but it's heavily implied in the last trailer that features of Ganondorf is elements of Demise, from what anyone could tell. That and when we see Zelda, she still has short hair, but near the end she looks like this and is firing a massive beam of light from her hand.
For all we know, this could be her Fierce Deity form or a fusion with Midna (gasp!), but everything seems to be leaning to Hylia vs. Demise.
Technically, I guess this is a spoiler, but they did put it in the trailer. I would've kept it under wraps, personally, but oh well.
