Think about the books as a whole. Everything GRRM wrote, everything the characters said or thought could possibly be interpreted in any number of ways. As an aspiring fantasy novelist, I have to admire characters who speak in riddles, regardless of their intentions in the story itself. Toward the end of book 1, when Daenerys finds Khal Drogo watching the sunset after Mirri Maz Duur "saved" him, Dany asks MMD when Drogo will be as he was.
(PS, sorry for the long post, I've just got a lot to say.)
Here's MMD's answer:
"When the sun rises in the west and sets in the east... When the seas go dry and mountains blow in the wind like leaves. When your womb quickens again, and you bear a living child. Then he will return, and not before."
Why did Martin write MMD's line this way?
Obviously in the books, Dany is still in Slaver's Bay, in Mereen, but in the show, she's now taking Westeros by storm! SO, here's my theory connecting East and West...
PART 1: "When the sun rises in the west..."
Which house sigil features a sun? House Martell.
Where is their seat? SUNspear.
Assuming Martin goes in a different direction from the show, I believe House Martell could join the war in support of Daenerys and venture north out of Dorne.
The SUN RISING IN THE WEST could possibly foreshadow the Dornish army taking over the Westerlands (now that Tywin's dead and Tyrion is headed for Daenerys), making Casterly Rock into their military base, at least for now.
PART 2: "When the seas go dry and the mountains blow in the wind like leaves..."
The SEAS GOING DRY could refer to the end of House Greyjoy of the Iron Islands. Who remembers way back when Jojen and Meera Reed were with Bran in Winterfell? Y'all remember Jojen telling Bran of his dream where the seas close in and flood Winterfell? Shortly after that, Theon Greyjoy took control of Winterfell!
Then there's THE MOUNTAINS BLOWING IN THE WIND LIKE LEAVES. I'm sure by now that EVERYONE who watches the show is anxiously looking forward to Cleganebowl! I'll admit I am too. BUT will Martin pull this off in the books as well? If so, I see MMD's line foreshadowing Sandor (AKA the Hound) coming out on top, bringing about the end of the Mountain.
PART 3: "When your womb quickens again, and you bear a living child."
At this point in the show, Daenerys is with Jon and they were consummating their love, despite being related. I ask you, what's the point of everything if she doesn't get pregnant? Now here's where MMD's prophesy gets a bit more tricky. After everything, she says, "...Then he will return, and not before." She didn't specify THEN DROGO WILL RETURN, she just said HE. Thinking out of context, HE could mean any man in Dany's life, or just the right man for the story's sake! MEANING...
Dany + Jon = full public resurrection of the Targaryen line
D + J = the end of the Night King
the end of the White Walkers
the end of any possible future Long Nights
In short, I believe MMD's prophesy in the east is referring to events in the west, where the more prominent parts of the story take place!
What do y'all think??