Formerly the the resistance and kaiser army, the united group was now known as the liberation front army. The moment they had opened another door the led further inside the underground facility, the environment had drastically resembled the labyrinth of trials layout based on what they had heard from the stories of those who had conquered the trials. So the whole Arcadia region was just something like a bonus content that added to the difficulty of the trials and made it realistic than a boring tutorial in awakening someone's powers, which was why it was called as a nightmare rather than a trial.