How Impa's Prophecy Links With BOTW2's Trailer

In this photo, which comes from Impa in Kakariko Village, we can see that the hero has a somewhat brightly colored hand, compared to the rest of his body which is red. 

If you can recall BOTW2's trailer, you may remember Link doing something that looks a bit like absorbing the power of the sealing hand.

This makes me think, what connection is there between the prophecy and the trailer? How old is this sealing hand thing? 10,000 years? Older?

What is the purpose of the sealing hand, we see that in the trailer the sealing hand is holding on to someone that looks like Ganondorf, and in the prophecy, we see the hero is using something that looks similar. Maybe this hand is the key for sealing Ganon?