The Woodland Empire came shortly after the fall of the Sacred Empire and inherited their language. The Ten Thousand Demonic Beast Array Book appears to date from this time. Most likely this Empire did not stand long enough to form an era as the demon beast riot that started the Age of Darkness happened around this time.
Inside of the barrier, Nie Li and his friends come across the Silver Winged Family. They speak the Woodland Empire's language and have been within the barrier, since the demon beast riot 1,000 years ago. In order to gain their trust, Nie Li says that he is a descendant of the Silverlit Family who were allies of the Silver Winged family in the past.