Here is the history of the world of Sacred Seasons, as explained by one of the creators of the game:
Sacred Seasons is a world that exists in an eternal state of cyclical change. Much like a wheel spinning around in a complete rotation, an age will come into being, built along a particular set of mythological and magical rules, flourish, then eventually die away and be utterly forgotten only to be replaced with another. Think of these like the spiritual equivalents of big bangs and big crunches. The world creates an entire mythological pattern for a time which might be 'gods' or 'spirits' or so forth. The driving force isn't always the same but is appropriate to the people who will experience it. There are only a few constants. Firstly an age winds down when its legends and myths are utterly forgotten. Secondly each age has a constant driving force - usually a kind of hub that it's focused around and several major forces that keep the age turning around this axis. Thirdly, and somewhat less importantly, there is a force outside all this, a kind of creator. called The Great Mystery. It doesn't interfere, relying on the hub and the major forces to keep things ticking along. This has been going on for a very very long time and nothing has ever broken this cycle.
At the end of the last age, which was a kind of primal, cave painting/tribal drumming age of blood and stone, the last great shaman refused to die out along with the rest of his people and hung on and on, surviving the end of his age and the birth of the next one, his name... Lord Root. He is the only thing in the world that isn't meant to be and as a result he is able to bend and twist it into new and horrible directions. Imagine the world is a book written by the Great Mystery. One that ends 'and they lived happily ever after'. All of a sudden a character appears in the book that they, the author, have no control over. One who kills off main characters, derails the plot and does his best to ruin it entirely. Lord Root is not bound by fate, obeys no laws and possesses not only incalculable amounts of magic but magic from a time that predates the seasonal cycle. Unlike everything else in the world Lord Root's magic works off an older long forgotten solar and lunar one. Ironically his source of power is also his weakness. Almost all his vast will is used keeping himself alive and any great spell or expenditure of energy will see him rapidly age as the era tries to reduce him down into dust.
Every good villain needs a motivation and Lord Root's is a desire to derail creation and reclaim his lost age. An age finishes when all the tales that can be told and all the dreams that can be dreamed have occurred. It and its inhabitants are exhausted and the universe gently releases them to their final rest. It's a reward, not a punishment but Lord Root, despite his intelligence and power hasn't been able to see it as anything more than the latter. Rather than join his people in whatever awaits an age's people he lives on horribly twisted, exhausted and in spiritual agony.
His goal is to wind down this age much much faster than it should and use it's energies to remake his old lost one. Almost as a way of spitting in the face of the universe more than anything else. He's been working towards this for eons, corrupting major spirits away from their designated roles, unleashing magic to throw entire lands out of balance and most recently launching his armies at the Hub.
The Hub of this age is the White City and it's ruler, the mythical White Hart. This place was the center of the Heartlands. Think of every single dream city or depictions of heaven on earth or Atlantis and you're getting the idea. Shining white walls stretching for miles. Rooftop gardens. Hundreds of thousands of lanterns winking over wide clean canals. It's like the best bits of every great ancient city on earth. The Samarkand Bazaar. The Constantinople old quarters. Paris' catacombs. All mingled together and sprawling out away from the Palace of the White Hart, a vast mucha-esque (the art deco artist) domed structure.
The White Hart herself was an Aslan (Narnia) figure, someway between human ruler, Ozma of Oz and daughter of the Great Mystery. Appearing as either a young faun or a gentle adolescent girl her mere presence inspired poets, created heroes and so forth. Think of those stories where people catch glimpses of the Virgin Mary or run into a divine messenger waiting for them as they walk along a road and their life is changed forever.
Serving her, and acting as the ages gears were a number of spirits, greatest of whom were the Cycle, the 4 season spirits much of the game is based around. These 4 spirits empowered the world's heroes and heroines, were the basis for most spells and each was said to watch one of the 4 directions away from the city, guarding it against attack and anchoring it to reality.
To cut a long long story short, Lord Root came, attacked and ravaged most of the city. It's heroes fell to his armies blades, it's walls and gates were broken as he moved towards the palace and guardian after guardian either died in its defense or turned traitor and betrayed the White Hart. As Lord Root's armies advanced the sky above them turned black into night. At the height of the conflict the sky looked like a patchwork of day and night with streams of sunlight falling down through black evening clouds. In the end the Hart fought Lord Root and while she managed to protect the palace was terribly wounded and fled into it's depths.
All seemed lost when her last servants, the four spirits of the cycle cast a great spell that effectively moved the center of the city and her out of time, breaking the anchors, locking the palace and theoretically protecting it forever from Root. The ritual to do this was enormous and complicated. Bits of the city were used as keystones to stabilize the magic. The great keys to the palace gates were locked and enchanted. Their shaman gave up their lives to cast the smallest parts of the spell while their warriors held back Lord Root's forces. And in the end, the ritual was cast, the city shimmered and vanished forever, and despite the terrible cost both it and the White Hart were protected forever. Or so they thought.
Root is nothing if not patient and simply turned his attention to the cycle. If they have keys that locked the city away from him, well then, he and his agents would find these keys and open the closed gates. If they had made binding spells that hid those gates from his eyes, then he would tear the spells from their shaman. If they had hidden keystones to the White City in the center of a mountain he would grind that down and break it open like a new egg. To accomplish this he has given orders to his most powerful minions, the Bore Lords to keep watch for these hidden relics and to undermine and destroy the servants of the Cycle. And in the past thousand or so years they have been remarkably successful. Most of the Heartlands have forgotten the Cycle who protect them, with shrines long abandoned and hardly anyone empowered by them anymore. You will represent the best and last hope of the Cycle.
The starting area where the players arrive is one of the great Cycle shrines, now fallen into ruin and a tempting target for one of the servants of Lady Stitch, the nearest Bore Lord.