Unsealed Hero

After a brutal and bloody battle, the hero Nathan defeated the overlord and brought an end to the hundred year war, at the cost of his own life.
Or so the story goes...
Nathan awakens in a woman's bedroom, with no idea how he got there. As she leads him to her organization's base, he quickly discovers the world is not the same as he remembers it. Where once there were villages and castles, now there are sprawling buildings and skyscrapers.
As he tries to piece together what happened all those years ago, a familiar voice asks him:
"Will you save this world once more, as you did all those years ago? Or after learning the truth, will you reshape it in your image? I await your decision."