The TOTK/BOTW Misconception
I have nonstop seen "10,000 years before...", "Zelda was a dragon for 10,000 years..." It drives me CRAZY.
In Breath of the Wild we get the lore of the calamity coming forth every 10,000 years. This is why the Sheikah created the divine beasts most likely directly in response to the calamity of their time. This happened 10,100 years before Breath of the Wild's gameplay, and we can infer that this reoccurring event happened enough times for them to realize that it would happen again and prepared fore it.
This all basically says the calamity had come several tens of thousands of years. And the calamity only began because of the gloom seeping out of Ganondorf's sealed body beneath the castle solidifying into malice.
So to clear up the confusion, Tears takes place several tens of thousands of years before Breath of the Wild, and Zelda was a dragon for just as long. As for the sky islands, I still can't quite figure it out.















