Seath the Scaleless was meant to be slain by the Chosen Undead, instead he finds himself wrenched from Lordran just before dying and abruptly tossed into a new role as the teacher of a kindred spirit: a pony called Twilight Sparkle.
One freak moment in time brings forth Equestria's greatest challenge yet, not from the lands it holds dear but from the stars that have watched over it since time began!