World Out of Time
The fortress wall of the world of this World Wood Tree was made on those walls. But the constant attacks of the Brimstone Beast that raged during the past two years had left a massive hole on the eastern side of the tree.
The Elven kingdom exterminated the Brimstone Beast to the west of them since there were no civilizations on the other sides of the tree since the World Wood Tree stood near an ocean that covered the north and southern regions.
And the Brimstone Beast could not fight well in the waters.
The eastern side, constantly being bombarded, was also where more than fifty percent of all the elves and other races fought and defended. As the elves were naturally good archers, they created forts all over the openings and cities inside the trunk, and no Brimstone Beast could ever reach the gates they created. The archer's arrow quickly shot down even Brimstone Beast that took the form of flying creatures.