There are also various kinds of troop buildings in the Castle of the Undead, which are designed to automatically produce different troops every week. These troops that emerge due to special troop buildings all appear within the ancient Castle of the Undead.
This is also why the eight Lords of the Undead possess such a vast and elite group. They are born from the deathly aura of the Castle of the Undead and are naturally much stronger than the Undead creatures outside the ancient castle.
If all the Undead creatures in the entire Secret Realm were to be unleashed, launching an Undead onslaught directly at Tokyo, even if it couldn't completely destroy the national capital, causing partial damage should be doable, right?
Moreover, from what Yamamoto Ichio said, he knew that in order to deal with the Great Xia Empire, this time the Coalition of Nations had almost dispatched all their elite forces.
