The Forgotten Legend

After conquering and unifying the greatest realm known to mankind about 1000 years ago, this mighty hero, chosen by the gods, laid herself to rest, vowing to return should her kingdom every be in peril.
Now is the time for her to awake from her slumber, only to see all remembrance to her eradicated from history. Who is this new dynasty, claiming to be the rightful rulers of the kingdom and why for the god's sake did she return in the first place?