Rainbow Dash meets her untimely demise when she creates the greatest sonic rainboom the world has ever seen, and her friends learn to cope with loss and while others continue her legacy.
Hades, Lord of Death and God of the Underworld, is bored. Residing in Tartarus gets tiring for a God. So he decides to visit Equestria for a bit. And maybe make new allies so he can take over Olympus.
What if neither sister won on that faithful night against each other. The elements choosing a younger alicorn to wield them, and end the fight. Now skip ahead a thousand years and our story begins, with a mare by the of Moondancer.