There once was an era in which the earth was inhabited by gods, humans, and an evil deity from the underworld known as the Demon God.
Under the flag of the holy maiden Vitoria, humans fought against the spirits, or monsters, who worked as the Demon's pawns for ages.
– God's Era, Year 395.
A technique for capturing monsters into a magical tome called a Sealbook was invented by the first royal alchemist, Siegdrad. A new, special class called Libras handled this sealing magic, and they garnered tremendous results in regard to monster suppression.
Thanks to their efforts, the monsters' population plummeted, and eventually the Demon God herself was sealed away. The world began to operate under the rule of humanity.
Then came the King's Era, Year 1. Vitoria had achieved continental unification through the hard work of mankind, and succeeded the throne as First Queen of the Kingdom of Romulea.
Kingdom of Romulea Founding History – Chapter 1, Section 10.
Some time has passed. It is now the King's Era, Year 499...
The stage is the Royal Library of the Kingdom of Romulea. Here begins a new story...
Source: The Game Website.