In the Nintendo Switch livestream, Reggie Fils-Aimé revealed the map of Hyrule that comes with the Legend of Zelda: Breath of the Wild Master Collection. On the back of the map, there’s a tapestry that shows Ganon surrounded by mechanical soldiers and 4 large beasts in each corner.
The tapestry is also outlined by Sheikah text, that YouTuber Zeltik and his fans have painstakingly translated from Sheikah, to Japanese, and finally into English. They believe it reveals the backstory of Breath of the Wild, and thus possibly contains spoilers for the new Zelda game.
Their rough translation reads, “Hylians pass stories of a destined time long past where multiple races lived and worked together in harmony. The Sheikah Tribe’s blue aura breathed through the land and this mutual prosperity continued until a cataclysmic disaster stuck. The Hero and the Princess attempted to seal the terror which became known as the Calamity Ganon. Divine beasts awoke from four directions and deployed a mechanical army which made the King and his people fearful. They fractured Ganon’s power and sealed him but the Sheikah were banished from the land ever since.”
If the translation is correct, it gives up one of the bigger mysteries surrounding Breath of the Wild, why Link wakes up alone in a shrine in a ruined land plagued by mechanical beasts.