If the fourth floor is cleaner and tidy, it is because the zombies have not entered and there is no problem, then the fifth floor underground will be interesting.

On the fifth floor, it cannot be said to be clean, but a sterile environment. Such an environment cannot be created, and it can only be the previous sterile laboratory.

Now, this sterile laboratory has no experiments. There are only twenty alloy cabins that are unknown to use. Some of them are like dormant warehouses, but their uses are absolutely different.

In this alloy cabin, through the glass, you can see that there are men and women, three men and seventeen women, and I don’t know if it is a human or a zombie.

There are two more floors down, and there is a huge space, but there is not much.

On the sixth floor, there are some firearms and weapons and equipment that are unknown. The firearms are randomly discarded there, and the equipment is operating.

The seventh floor is different from the sixth floor. At the entrance of the seventh floor, there are two burly zombies similar to the second floor. I don’t know what it is inside, what is worth the zombies’ handling, or why would a brainless zombie guard there?

All of this was underground. Yun Yi didn't know that he could only see the densely packed special zombies in the city fortress, all kinds of them, and even some special zombies that had never been seen in it.

Time passed day by day, and the swarm had already hatched the main nest group on the periphery. Because of killing countless zombies, the biomass reserves have now become extremely abundant.

Moreover, Leviathan has brought back the gas resources collected from gas planets and the mineral resources collected from resource stars, and the insect swarm can usher in a huge wave of vitality.

With the full firepower of all the main nest groups, the insect swarm expanded from the original 10 million to more than 20 million. It was not that the biomass resources were used up, but that the gas and mineral resources brought by Leviathan were used up.

While letting Leviathan collect it again, Yun Yi felt that the built-in insect swarm of 20 million should have been able to push the remaining zombies with more than 2 billion left.

Not to mention anything else, just over five million poison explosions are not something that can be resisted by the dense zombie group.

After making this judgment, Yun Yi did not hesitate and directly ordered the entire army of insects to attack. The destroyer skills were used to lead the way, the cockroaches and thunder beasts charged, the poisonous explosion followed, and the remaining insects units were followed.

The destroyer sprayed the bile with a wave of corroding, directly clearing the dense zombies. Whether it is ordinary zombies or special zombies, they can't die anymore.

Before the subsequent zombie group could block the gap, the thunder beast and cockroaches had already launched a charge. Their mission was to open the way. The first target was not to kill. They just rushed forward in a daze, and they could rush forward wherever they could.

Under the leadership of the Thunder Beast, the cockroaches charged for ten kilometers, and were blocked by a large wave of fat zombies, a large wave of self-explosion zombies and a giant zombie every few dozen meters.

As the charge ended here, millions of poisonous worms followed closely, rolling in along the paths opened by thunder beasts and cockroaches, without attacking any zombies during this period.

These zombies who were washed away had subsequent swarm units to clean up, and the lurkers and the swarm flying units in the sky were not followed by the show.

The poisonous worms that are rolling in have their own mission goals, which are various powerful special zombies that block the charge of thunder beasts and cockroaches, especially the giant zombies that are more than ten meters high that can fight with thunder beasts and make cockroaches passively buried.

Before the poisonous explosion worms could catch up, there were dense explosions one after another. The sound was similar to the explosion of a bucket full of water, and it was just a huge slug.

These are the movements made by the self-explosion zombies. The self-explosion zombies of countless people exploded. The cockroaches around them were directly emptied, and even the thunder beasts that were closer were also very explosive.

There are even thousands of unlucky thunder beasts who were directly killed by explosions. Although not many, there are indeed some. They are surrounded by self-explosion zombies, which is impossible.

With its size advantage, these self-explosion zombies are more powerful than self-explosion worms and are very resistant. If they are not running too slowly, they are really invincible.

The front row of cockroaches were cleared, and the cockroaches behind were quickly filled.

Now there are no self-explosion zombies in the zombie group, but there are fat people and giant zombies. What should be blocked should be blocked. If they are allowed to rush over, the poisonous zombies will not be able to exert their maximum attack power.

More than ten seconds later, the poisonous explosion worm followed, and there were continuous explosions. In addition to the explosion, there was also the sound of "hissing" objects being corroded.

This time the explosion was a poisonous worm, and the zombies were killed. The fat zombies and giant zombies who had already vaguely broke through the defense line of the cockroach thunder beast disappeared under the attack of the poisonous tide.

Behind them are tank zombies, and the poisonous explosion torrent did not stop at all. After the zombies blocking the road were cleared, they rushed directly to the tank zombie group.

With the sound of explosions and corrosion, after a few minutes, countless tank zombies and ordinary zombies they used as shells were cleared.

At this time, cockroaches and thunder beasts followed again and blocked the zombies that were coming.

The poisonous explosions hugged behind cockroaches and thunder beasts, and went to explode self-explosion zombies and fat zombies that ran out of ordinary zombies from time to time.

You can't move forward any further, otherwise the subsequent insect swarm will be disconnected. Although the formation of the zombies within ten kilometers has been dispersed, it is enough for the insect swarm to clean up for a while.

In addition, if you need to worms and later lay a worm blanket, that's all.

With the advance a few days ago, it is now less than 60 kilometers away from the city fortress. If you take a few more charges like this, you can attack the city fortress.

The insect swarm took three days to be separated by the zombies and cleaned up all the zombies that were separated.

For such a zombie group, the insect group cannot encircle and annihilate it for the time being, so it can only open a breakthrough. Now the breakthrough is open, but it must also ensure that the breakthrough is not blocked by the zombie group that rushes into it.

There was no way, Yun Yi could only let the lurker block the breakthrough opening of the insect swarm.

The current situation is like this. If you compare the zombie group to a circle, the worm group will be a triangle that breaks into the circle.

The circle formed by the zombie group has an additional triangle mouth. Now, the circle wants to close the triangle mouth.

This is why Yun Yi wants the lurker to block the outer edge of the breakthrough in the formation of the insect swarm. If the breakthrough in the just-opened one is closed again by the zombie group.

Not to mention that the efforts made are in vain, just talking about the most cutting-edge insect swarm units, but there are high probability that they will not be able to come out. With too many ants, they can really kill the elephant.
Chapter completed!