Dungeon

Dungeons are locations around Eos that are darker and more dangerous than the rest of the outside world.

End-Game Dungeons
Upon completing the main story line, the player can obtain the Dungeon Seal Key from Ezma at Meldacio Hunter HQ. With this key, the player can now open the mysterious locked doors hidden in each of the Lucian dungeons. These are known as the "Menace Dungeons" due to the quest line - Menace Beneath Lucis - that is acquired upon accepting the key. The quest and the key can only be obtained upon completion of the final story mission.