I've seen the video, and it's surprising that no one else has thought of this.
Remember the poem in S2? If not, here it is.
From a distant land in the East, from across the sea, he shall appear.
He does not know of the strangth hidden within him.
The strength that would destroy him.
The strangth that would fulfill his wishes.
When he is ready he shall seek me out.
And we shall brave together the rocky path.
I shall wait...
This encounter has been my destiny since ancient times.
A Dragon shall emerge from the Earth, and dark clouds shall obscure the heavens.
A Phoenix shall descend from above, with its wings will create a purple wind.
In the midst of the pitch-black night, a morning star shall glisten, alone....
Is it me, or is that exactly what happened in the trailer?!?!
"A morning star shall glisten alone"
What was Shenhua holding in her hands at the end of the video?
I rest my case.