The complex terrain of the underground space has no place for the air force, but the hundreds of meters high tunnels connect the underground spaces like various honeycomb foams straight up and down, which complicates the entire underground space environment.

It should be said that any force with World War II technology and complete the manufacture of standard metal parts has the ability to make elemental fuel rod technology in the underworld. The elemental-rich glowing seaweed of the underworld is the ultimate strategic resource that directly unlocks black technology.

Three years ago, the lords of the underworld received the news that the surface world exploration forces were all wiped out, and the nobles who led the army were all wiped out, and they were very shocked.

The remnants of the soldiers who fled back to the underworld have questions about their ability to narrate, asking what happened to them on the surface? These low-level demons who survived the dense shrapnel harvest, their already ugly faces were filled with fear, and they repeatedly recounted words such as "flames, blood, huge steel dragons, ferocious roars" and so on, but what is the specific and complicated battle situation, these brave creatures fighting on the front line can obey orders, but it is a nightmare to expect them to flexibly feedback battlefield information.

Three years ago, the exploration team that had just climbed out of the surface was annihilated, and the entire underground world was quiet for a while. However, now the mechanical spiders of the underground world are fighting in complex caverns, and the machine guns and hydrogen incendiary weapons have caused great damage in the relatively narrow underground space on the surface, because the height of the rock space in the underground world is no more than 600 meters, and the radius of a space is no more than 50 kilometers. So the weapon doesn't need a long range, and even if you have this long range, you can't cast this kind of long-range weapon ballistics in the underground world of this hive structure.

So the combat effect of this spider mecha is very amazing. At the same time, it also allowed the Dawn Republic to get a lot of data on the battles in the underworld, the humanoid, this form was evolved by humans to adapt to the surface environment, and can climb on rocky cliffs, run in the jungle, and hide from trees. However, the underworld, which still seems to be a crevice, is well suited to combat.

The conflict in the underground world is intensifying, because there are too many depressions in the underground world that can be hidden, even the most complex mountainous areas on the surface are nothing compared to the underground world. What is the impact of complex terrain on modern warfare? Taking the Himalaya Mountains of the earth as an example, the Indian military has been exterminating the guerrillas again, the heavy artillery cannot move, the helicopters keep crashing, and they can only rely on the infantry to fight.

The height of the rock dome in the underworld is destined to be useless. Therefore, the heavy artillery also wants to be deployed, and this underground world happens to be a good battlefield for spellcasters, even if the Republic of Dawn has a magic probe, participating in this kind of underground world war, even if the magician uses magic even if it is detected by the magic probe, due to the complex terrain ahead, you can't carry out the strike. It's like fighting in a room, where you hear enemy gunfire in a room and you only know that the enemy is in front of you, but you can't find it and destroy it. And on the plains, on the battlefield where the snipers of both sides compete, whoever wants to shoot first will directly expose their position.

And the scene that Zhao Weiguo observed in the underground world through his talent, and then showed it to Wang Long and Jiang Le of the Son of Heaven Alliance, made these two colonels staggering about the complexity of the underground world.

In the underground world, located directly south of the continent, this is where the three Evolution Colonels of the Heavenly Son Alliance have placed their bases. Now these three colonels barely occupy twelve underground world cavities, the large of which are thirty kilometers in length and width in diameter and four hundred meters in height, and the small ones are only 7 kilometers in length, width and diameter.

It can be seen that these underground spaces are difficult to occupy, of course, after an underground cavity is occupied, it is basically a perfect rear, and there is no need to worry about conventional weapons. Even nuclear weapons can only destroy a cavity at most, and the place surrounded by other cavities is still protected. Of course, each cavity is strategically located, and the other cavities are often connected to a few small caverns.

There were cavities that were completely occupied by the three Evolution Officers, and there were also those that were attacked. The lords of the seven underground worlds have discovered that the underground alliance is leading the caveman rebellion in the underground world. These Underground Lords reacted quickly. First of all, the small lords around the forces of the Underground Alliance joined forces to launch an attack on the Underground Alliance established by the Knights of God.

Three of the underground cavities have become battlefields, Zhao Weiguo observed a maximum of 15 kilometers, the narrowest 4 kilometers of underground space, this underground space is like a propped up quilt, but it is this small underground space and the area of 60 kilometers up and down, left and right, there are as many as 482 rock tunnels. The four largest of these tunnels have a maximum diameter of more than a hundred meters. Two of them are in the hands of the underground alliance. The other two are in the hands of the native races of the underworld. The war began in this complex environment.

The giant spider was moving forward almost step by step, and in the dark underground space you could see the bright light dragged by the bullets, spraying in one direction, but on the other side, the huge magical elements in the complex terrain formed like a vortex in this small space, the huge stones separated from the rock dome, and the pure hydrogen chloride separated from the salt mines. Thirty percent of the hydrogen chloride is concentrated hydrochloric acid, and the acid rain released by these magical races in the shadows sprinkled on the area where the four-legged mecha is located, and immediately emits a corrosive hissing sound. A large amount of thick acid smoke rises as the acid rains on the ground. However, at this time, a large number of slippery loaches crawled quickly against the ground, and the scales on their bodies reflected black and bright colors in the firelight.

At this time, a large number of bullets were sprayed from the acid smoke, and some of the underground creatures that launched the attack were fixed in the ground by the bullets, and the fangs turned out, but the shots from the acid smoke were obviously blind and did not have the effect of suppressing the fire. These attacking, vicious-looking underground demon soldiers are very simple-minded, but they are also very brave.

Soon approached the machine-gun firing position. These demons with very strong muscles rushed near the mecha and ripped off the fragile parts of the quadruped mecha's joints. The huge fist smashed open the glass cockpit and bent the protective fence of the anti-theft window structure, and the sharp claws pulled the mecha pilot's head, and pulled it out of the cab in this way. Sometimes the tugging is too violent and the head is pulled off directly.

However, just as the demon class was slaughtering the underground alliance, the position where the mecha soldiers were located, there was a muffled sound from another position, and things like gas canisters were thrown over, and after these gas canisters fell into the position, half a centimeter later, the explosives evenly distributed on the periphery of the iron sheet exploded. A large amount of gas overflowed, and in an instant, the flames engulfed everything, and a huge ball of fire swallowed up from the position, floating directly to a position two hundred meters away from the dome, and quickly dispersed in the sky into flame ripples.

The course of the war was extremely cruel, and the two sides fought in this space with a miasma, and a large amount of oxygen was consumed. The battlefield was strewn with blood-soaked rubble, large and small. The two sides repeatedly tug-of-war along their own lines of control, and the magical creatures took turns in this narrow, unobservable space. The huge rock golem advanced under fire, and the chest was directly shattered by an armor-piercing bullet, and finally fell. It smashed into the position where the mecha was located like the ground shaking, burying the three mechs in the position that had no time to retreat.

Seeing that Zhao Weiguo came to such a hot battle scene, Wang Long looked at the mecha soldiers in the training ground in front of him, and asked Zhao Weiguo, "How long have they been fighting?" Zhao Weiguo said: "A month ago, the war began to break out here, and the kind of hot war you see has only happened eight times in this month. Each session should last no more than three hours. It should be Marshall that there is a problem with the supply of ammunition to them. The iron in the hydrogen tank can be obtained by electrolysis of iron oxide, hydrogen can also be obtained by electrolysis of water, and the synthetic ammonia system can also be synthesized by electric heating and electric pressure. In short, all industrial materials must be smelted by electricity...... But their electricity consumes too much in the war. ”

Jiang Le asked, "If we enter the underground world, how should we fight in this situation." Zhao Weiguo smiled and said: "Our chemical raw material is coke hydrogenation to produce alkane ethylene. In the face of such a war, my advice would be to use cloudburst bombs to create walls of fire to sweep through in an hour, and then have the mech infantry use flamethrowers to spray all the way through the passages in the various underground spaces. Flames will expand along all crevices when used in small spaces. ”

Jiang Le added, "Also pay attention to the narrow passages that some mecha infantry can't get into, but the creatures of the underground world can pass through. They must not be given a chance. "The three Evolution Officers of the Celestial Alliance carefully discussed the situation that the Dawn Republic needed to pay attention to if it needed to use force in the underground world.

However, continuing to look at the bigger picture, everything is actually planned by the highest planner.

Tianyun Space, the existence that often quietly intervened in Yuan Miao's long history, is ready to come again after a thousand years in Yuan Miao's history. In the eyes of these traversing monsters in the void that can cross many planes, there is a time period for invasion in planes like Yuan Miao and Titan. This time period, from the end of the Magic Empire, is actually based on the time point where Ren Di is located and ends at 20,000 backwards, this time period.

The history line for this time period is very stable and fixed. And crossing the historical line mastered by the monster is that the history of these tens of thousands of years is randomly inserted into a point, and the flow of the historical line forks into another parallel plane. In other words, the Tianyun Space can release traversers at will in these 40,000 years. Make a plane history line development that is influenced by itself. Just like a TV series, the audience on the periphery of the TV series can play back and forth, and during the screening, they can casually insert their favorite actors into the performance.

This historical line, the traversal monster has been interfering for 40,000 years since the end of the Magic Empire era#, and it can be regarded as mastering this historical line, and in the next process delivery process, it will advance the time period of the first delivery a little bit earlier, and take back the time of the last delivery back to the time of the traverser, slightly delayed. With the release of Tianyun again and again, it can be seen that the time period mastered by Tianyun Space in this plane is also constantly expanding.

Of course, the traverser does not know everything about the plane, and the traverser is the existence of the plane layer of time and horizontal, and the understanding of a plane depends on the tentacles of the interfering world of the traversal monster, which belongs to the traverser of the traversal monster to explore.

As the number of deliveries increases, they become more familiar with the places where the traverser can move, and become aware of the future development of the plane in any direction. It's like the protagonist of Tomorrow's Edge has a clear understanding of the various changes in the world throughout the day after returning to the beginning countless times. Tianyun will know how to intervene in the assignment of tasks, so that the next historical development of this world meets his own requirements. Then this plane will be completely mastered by Tianyun.

Evolution and the Tianyun Space are both fourth-order existences, but evolution is not a traversal monster, evolution is another thing.