This marked the end of the first exchange in the battle. It ended with the allied defenders losing a wall, some rank 5 bombs, and some troops, while the invaders temporarily lost the use of 10 mobile fortresses.

The war resumed after the invaders pulled out their mobile fortresses from the holes in the ground and filled the holes with sand and rocks. After the holes were filled, they moved over the safe ground and proceeded to move close enough to bombard the second wall.

There were 10 walls now. But each one was still 10 stronger than they should be despite the loss of one of them. This was thanks to the assistance of the buttress walls.

The defenders had been building buttress walls even before the first wall fell. The lull in battle when the invaders were covering up holes and traversing hostile terrain gave the defenders more time to build the buttress walls needed to maintain the strength of the overall fortification.

So the second wall was able to withstand the first round of firepower from the invaders without falling immediately. But the defenders knew that they couldn't let the current situation continue, or there would be a repeat of the first exchange.

The patriarchs ordered more buttress walls to be built, and if they ran out of space to build more buttress walls, they ordered people like Arthur to improve the previous ones and enhance their power.

In the meantime, the patriarchs activated their flying ships and used them to attack the invaders. There were 15 flying ships in total sent to attack.

Some of the flying ships were at rank 5. There were exactly five of them at rank 5. One came from each sect. The remaining 10 were at rank 4.

The arrays of the flying ships had been incorporated into the arrays of the fortifications, which allowed them to be exempted from the no-flying rule. This gave them the advantage of maneuverability that the mobile fortresses on the ground lacked.

The invaders finally felt some danger. This was because of the rank 5 flying ships. The five of them possessed enough firepower to threaten the defense of the flying fortresses.

Things went well for the defenders immediately. The flying ships quickly took down three mobile fortresses. But the invaders also retaliated.

The mobile fortresses were unable to dodge as easily as the flying fortresses, but they had something that the flying fortresses couldn't match at all. This was guns and firepower.

One of them is called a fortress, while the other is called a ship. From their names, one can tell how suitable they are for battle and war.

The mobile fortresses had more guns. They were also more durable than the flying ships.

Lastly, even if they are damaged and can't work anymore, they can't fall down since they are already on the ground. But for the flying ships, any pause in the operation of their engine meant a fall to their death that would ensure that a minor injury became a fatal one.

All of these are why the mobile fortresses were able to take out two rank 5 flying ships and six rank 4 ones in exchange for the two mobile fortresses that they lost.

To top things off, the two mobile fortresses were not completely destroyed and could still be repaired and put back into battle. Some of the flying ships could also be repaired, but most of them, especially the rank 4 ones, were done for after falling from so high.

By the looks of things, the defenders were winning the round of exchange. This was something that both sides recognized after counting the losses on both sides.

This situation forced the patriarchs of the five sects to bring out another card. They activated the special formations that they had been personally installing since the start of the war.

Three special formations were activated. Each one appeared as a ring above the second wall. This was because they were using the walls as their foundation.

The first formation is an obscuring mist formation. It produced black mist that blocked every form of perception.

For everyone trapped in the black mist, the whole world became a dark, silent, and empty void. This was dangerous because even nascent soul patriarchs could get lost in the dark mist.

Once this obscuring mist took effect, the mobile fortresses lost sight of the wall and their allies. They became lone boats in the darkness.

Fortunately for them, the barrier shields around the mobile fortresses could block out the obscuring mist. But this was unlikely to be the case for much longer because the second rank 5 formation that was activated was the lightning serpent formation.

The lightning serpent formation produced giant blue snakes made entirely of lightning. These giant lightning snakes were then controlled to attack and bombard the mobile fortresses.

This wasn't the only means of attack that the defenders were using. The flying ships were still there and were still on the offensive.

The flying ships were exempted from the effect of the obscuring mist, so they could still see and still attack the mobile fortresses. Since the mobile fortresses could see them and shot at them, they were safe to release all of their firepower on the invaders.

The combined power of the lightning serpent formation and the flying ships showed its effect quickly. The mobile fortresses began to fall one by one. Their barrier shields fell, and the obscuring mist rushed into them. This created the right opportunity for the third rank 5 formation to take advantage of.

The third rank 5 formation is the cricket chirping formation. This is a formation that makes people hear the chirping of crickets as it destroys their minds.

The cricket chirping formation is a rank 5 formation for attacking the mind. Its mode of attack is sound and vibrations. As long as someone can hear the chirping of crickets, their mind will be attacked and slowly destroyed.