Yunwu City had a total of three walls, named the Major Wall, the Internal Wall, and the Palace Wall.
In terms of defensive power, the Major Wall was the strongest. After hundreds of years' reinforcement, the wall was high and thick. What's more, they had even invited the array masters from the Federation of Inscription to set over 100 Defender Arrays.
Although the Palace Wall, which defended the Palace, was not very high, the number of defending arrays and attacking arrays was more than that of the Major Wall.
Particularly, the Dragon-turtle Holy Armour Array, a Fourth Class array, which was 70% defensive power and 30% attacking.
Once the array was started up, the whole Palace would be covered. Even a warrior in the Fish-dragon Realm would find it difficult to break through.