Library

I accidentally encountered a group of tomb robbers during a collection... What exactly is the ancient country mentioned by the tomb robbers? What is the relationship between the mysterious disappearance of the foreign soldiers a hundred years ago and the destruction of the ancient country? Is there any connection between the mysterious girl and the destroyed ancient country? What is the connection between the zombies in the ruins and the gods believed in by the ancient country? The missing great-grandfather's sword is on the stone statue of the mythical beast worshiped by the ancient people?