As I've discussed at length before here[link], the world of George R.R. Martin's Game of Thrones (or A Song of Ice and Fire for the book folk) is a place of strange and ancient magicks that were thought to be extinct until very recently in the currently unfolding story. Why these forces are seeping back into the world is the cause for much speculation and debate, and unfortunately will continue to be so since we have to wait potential YEARS before either the show or the books can finish the tale. Until then, we have our imaginations, reddit, various wikis and forums, and the story as we know it so far. While the show is indeed a watered-down version of the books (soon to also be divergent from the source material, if the reports are true), many potential clues as to the origins and consequences of these magicks have been strewn about for those who care to see them. It can be easy and endlessly entertaining to remain wrapped up in the ruthless politics of Westeros and the lands across the Narrow Sea, but if you aren't getting a little concerned about the various doomsday-esque prophecies floating around then you aren't really paying attention! All these nasty weddings and would-be Kings serve to do is distract the long-complacent people of the Seven Kingdoms from the real dangers brewing in the North and within the lengthening shadows of the dwindling Summer-days. Let us delve into the ominous signs we know so far…
The Long Night is referred to mostly as a past cataclysmic event. Taking place thousands of years before the arrival of Aegon the Conqueror, which heralded the longest Winter on record; The Long Night was full of darkness, cold, famine and unspeakable terrors. We are slowly being given hints and signs that there may well be a second coming of this ultimate shit-show for Westeros, if not the whole known world of GoT. Our hints start early on with everyone and their Old Nans remarking that this current Summer has been one of the longest in recent history, a correlation that may lead to an equally long, if not longer, Winter-to-come. The Starks, one of the only rational and honorable houses in Westeros, have kept this thought in the foreground of their lives with their portentous House-motto: Winter is Coming. While this may seem only to attest to their well-known, no-nonsense ways and dour surroundings, these words may yet be prophetic to a darker understanding of things to come and could be considered a warning akin to the beloved, "Hold on to yer butts!" of Jurassic Park fame.
Less repeated but nonetheless dearly-held is the Northerners' belief that, "There must always be a Stark in Winterfell." Whether this is simply a tactic for effective rule of the region or something with more sinister consequences, we have yet to see, but with the current rates of Stark-dispersion we have ample cause to be concerned. Sansa, by birthright the Heir to Winterfell since the passing of her parents and eldest brother Robb, has been spirited from King's Landing to the Vale of Arryn with no immediate plans to return to her ancestral home. Arya has long been on the lam and, though she remains as badass as ever, is well on her way across the Narrow Sea to the land of Braavos (home to her mysterious face-changing friend Jaqen H'ghar, and her beloved, possibly-dead Dancing Master Syrio Forel). Arya also has her own small instance of prophecy/omen as Melisandre (in the show) sees many deaths and an alarming darkness in her during their brief but notable encounter. Bran is now safe (maybe?) in the hands of the Three-Eyed Raven and the Children of the Forest beyond the Wall to meet an imposing destiny of forgotten magicks and epic powers of Sight. His destiny seems to be picking up speed as the show goes on, though we still have yet to see if he can truly ever "fly" as his visions of the Raven have promised, and what this will mean for the Realm overall. Little Rickon has been taken somewhere we can only hope is "safe" and is otherwise completely out of sight, out of mind. That leaves our favorite bastard, Jon Snow, up defending the Wall from the masses of fleeing and war-minded Wildlings and the impending army of Others and their ilk. Suffice to say: there are currently no Starks in the smouldering ruins of dear Winterfell. This is already an unfavorable outcome, but it seems safe to assume it is about to get worse on an epic scale.
Rampant fan theory has a lot to say about the significance of a now destitute Winterfell and the fall of the House of Stark, as well as the implications of the adages of the Starks and Northerners alike. What is going to happen without a Stark in Winterfell? All we know for sure is it can't be good. Perhaps without the long line of Starks, as descended from Bran the Builder, to tend to the Wall and Winterfell (the greatest stronghold of the North) in their ancestral role, this looming epic-Winter will have the foothold it needs to develop into the next Long Night. However, this theory is not without its holes.
For instance, we see the first indication of the White Walkers' return in Season One: Episode One during the prologue with the Night's Watchmen disastrously discovering the remnants of a White Walker attack before being attacked themselves (this happens in much the same way in the books, as well). This would imply that the super-scary Winter is on its way regardless of the Stark-in-Winterfell rule, proving that Winter is INDEED Coming no matter what. Yet almost immediately after we see the Night's Watchmen being slaughtered by the White Walkers, we are introduced to our beloved Starks inflicting unfortunate justice on an assumed Night's Watch deserter (the audience recognizes him as a survivor of the White Walker horrors) before they stumble upon yet another ill-omen of things to come: the body of a Direwolf mother killed by the impaled horns of a Stag, leaving behind six young pups (one for each of the Stark children, bastard and all).
Obviously this Direwolf is a symbol of House Stark and more notably Ned, himself. As he is taken into the world of deceit and intrigue far to the South as Robert's reluctant Hand of the King, we see the symbolism turn horribly true when he is shockingly beheaded as a traitor in service to the Baratheons, who retain the stag as their sigil. Other than Robert's death, Ned's execution clearly starts the War of the Five Kings and the unraveling of the Seven Kingdoms.
Another mouthpiece for spooky omens galore is everyone's favorite Red Woman, Melisandre of Asshai. When not stoking Stannis' dour ego she is spouting off about Azor Ahai reborn and the savior of the Light against the Dark. This can be neatly folded into the fears of the Long Night (darkness) and the Lightbringer (be it a sword, person, or… dragon? Who knows!?) and its looming doom and/or defeat. She "sees" much of her signs in the fires of which she’s so fond, yet we have yet to be truly privy to her visions. All we know is she is betting on Stannis to be the savior of us all (yuck), and is hell-bent on seeing that it shall be done! Only in the last season of the show does she exhibit any inklings of doubt as to the interpretation of her visions and her wavering confidence in her powers (she has a very notable conversation with Thoros regarding his bringing-people-back-from-the-dead powers where it is mentioned that neither of them, by any rights or accounts, should even have these powers). Other than her renowned shadow-baby-making and poison-drinking abilities, we have yet to see exactly what she hopes to accomplish per her beloved prophecy, but we can bet that it will be freaky nasty for the inhabitants of Westeros and the world at large.
Danaerys Targaryen has her own menagerie of prophecies to contend with regarding the state of the world and her destined role in it. First being told her son by Khal Drogo is to be the Stallion Who Mounts the World (whatever that means… awkward), though he is later found to be lacking, what with not surviving and all. Then later, in her experience among the wizards of Qarth in the House of the Undying, she experiences a myriad of prophecy-like visions to test her determination in recovering her stolen dragons (this sequence is VERY different in the books, but the spirit of the experience is similar). Her visions in either book or show seem to portent her destiny to some degree, with much importance placed on the Iron Throne of Westeros. Anything mentioned in the books can be considered spoiler-y so we will avoid discussing them here, but the show gives Dany the vision of the throne room at the Red Keep, albeit deserted and exposed to falling snow; whether a vision of the past or future, we cannot tell, but the omen seems to fit with the Stark words "Winter is Coming." Additionally, she sees her former life with Khal Drogo paraded in front of her with her still-born son shown to be a thriving toddler; whether this is meant to simply distract her or cause her pain, again, we cannot be sure, but she leaves them behind all the same to seek her greater destiny with her three young dragons. This sequence, in the show, is not as heavy with foreshadowing as the books make it out to be, but there is still a potent air of prophecy in her visions. Though she leaves behind both the Iron Throne besieged by winter and her former family (Drogo and their baby Rhaego), her purpose seems to be to strive for something beyond simple rule of a kingdom or serving as a Khaleesi to the Khal of Khals and mother to the Stallion Who Will Mount the World.
All the under-explored and little-mentioned regions in Game of Thrones seem to have their own portents and omens regarding the end of the world, with many instances of similarity and overlap in the various interpretations. What we do know for sure (especially in the mythos of the show) is that the game of thrones is all well and good (except when it kills you of course), but Westeros and the rest of the civilized world really need to get their shit together before things get really bad. So beware the bloody weddings and deadly intrigues as the political arena rages onward, but do pay especially close attention to the ominous undercurrents of rumor and legend which seem to be leading us to a catastrophe unlike anything the World has ever seen.