After all, the defense area of the core star fields of the cosmic-level civilization is too vast.

Although for the sake of the development of the cosmic-level civilization itself, in each core star field, the three cosmic-level civilizations have used a lot of technical means and spent a huge amount of money to artificially relocate each important planet, change the orbit of the planet, eliminate the existence of unqualified planets, and make the planets in the core star field as close to each other as possible, maximizing the existence density of the effective planet.

However, the overall diameter of each independent core star field is measured in 10,000 light-years, and even if you cut through the outer interstellar void and just calculate the total diameter of the many planets at the core of the star field, it will be hundreds of light-years at every turn.

To protect such a huge area of core security area, the difficulty of nature can be imagined.

With hundreds of light-years of defense, this is a huge challenge for any security team. Especially as a large-scale astral structure, its defense system is not a simple plane defense system, but a complex defense space with a three-dimensional structure, which is an extremely difficult problem even in terms of the defense methods of a cosmic-level civilization.

Trying to keep all enemies out of the starfield's defenses and prevent any fish from slipping through the net into the defenses is a challenge that has never been seen before even for a cosmic-level civilization.

After all, the previous game between the ancient civilization and the three cosmic-level civilizations almost revolved around wormhole passages, and in the face of the ancient civilization's almost pervasive infiltration methods, even if it was just to defend against a wormhole passage with a diameter of tens of thousands of kilometers, the three cosmic-level civilizations had already racked their brains.

Around the front and back of the wormhole passage, the three cosmic-level civilizations have adapted and experimented for hundreds of years, and experienced countless failures and setbacks, before finally forming a complete set of systematic defense methods, and finally completely blocked the infiltration of the ancient civilizations from the wormhole passage, keeping the peace inside many core star fields.

Now it's time for the ancient civilizations to change the battlefield, no longer continue to fight with the cosmic-level civilization around the wormhole channel, but directly organize the fleet to carry out cross-star expeditions, which is naturally a new challenge for the three cosmic-level civilizations.

The defensive front of the entire star field, compared to the point at the entrance of the wormhole passage, is naturally completely incomparable, if the souls of the ancient civilization are allowed to run around, then there is really no possibility of defense.

But fortunately, for cosmic-level civilizations, on this new battlefield, they are not without their own advantages.

The biggest advantage is that the core star field and the surrounding star fields are also at a distance of more than 10,000 light years, such a distance even for the Iron Battlestar must start an ultra-long-range jump to reach it quickly, and for military warships, such a long voyage will take several years to complete.

More importantly, the souls of ancient civilizations themselves did not have the ability to cross the long star field. This is because according to the in-depth research of the three cosmic-level civilizations, the soul body of the ancient civilization itself can only reach the level of sub-light speed at the fastest speed in the void, at most the upper limit of one-tenth of the speed of light, so the only way for the soul body of the ancient civilization to penetrate into the various star fields of the cosmic-level civilization is to take a faster-than-light spaceship.

Otherwise, it would take hundreds of thousands of years to reach the core star fields across the void with only the speed of the ancient civilization's soul body itself.

And if the ancient civilizations had taken faster-than-light ships, they would have spent much less time navigating the void.

In this way, the war between the ancient civilization and the new stage of the three cosmic-level civilizations can obviously be converted into the interception war of the cosmic-level civilization fleet against the ancient civilization fleet to a certain extent.

The cosmic-level civilization must defend itself against the enemy outside the country, otherwise, if the battle is too close to the core range of the core star field, then the huge defense range is obviously impossible to defend at all, even if the cosmic-level civilization strengthens its defense, it will inevitably cause loopholes everywhere, giving the ancient civilization the consequences of taking advantage of the opportunity.

Considering that if the battle starts, it is very likely that the souls of the ancient civilization will abandon the ship and take further action, using their own undetectable characteristics to hide their existence and continue to approach the core star field. Therefore, in order to prevent the soul bodies of the ancient civilizations from penetrating into the core star field to the greatest extent, the fleets of the three cosmic-level civilizations obviously had to intercept the soul bodies of the ancient civilizations at least a hundred light years away from the defense range of the core star field.

Although an area a hundred light-years away cannot be said to be absolutely safe, at least beyond this distance, if the soul body of an ancient civilization wants to cross the void and infiltrate the core star field, it will take at least a thousand years.

A thousand years is obviously quite a long time even for the life of the soul body, especially if there is not enough supply in the void, maybe in such a long period of time, the soul body of the ancient civilization will starve to death, even if it is not starving, postponing the current crisis to a thousand years later, this is obviously a quite cost-effective thing.

With thousands of years of development, maybe the three cosmic-level civilizations have already made breakthroughs in some core technologies, and maybe the three cosmic-level civilizations will no longer regard the ancient civilization as a threat.

Even if you think about it from the worst point of view, after thousands of years, these attacked star fields will inevitably face the end of falling, with such a long buffer, the three cosmic-level civilizations obviously have enough time to migrate populations, or make other arrangements, in short, this attack by the soul body of the ancient civilization can be regarded as a failure in a short period of time.

Of course, if you have spare power, of course, the farther away the fleet of the ancient civilization is destroyed, the better, and the core star fields of the three cosmic-level civilizations will be safer, but this is also quite difficult.

Because the number of fleets and ships that ancient civilizations attacked each core star field was hundreds of millions, it was obviously unimaginable for such a large-scale fleet to intercept and destroy them all outside the cordon, and the number of fleets that needed to be mobilized.

After all, the forces of the ancient civilization are different from other civilizations, other forces, and if the three cosmic-level civilizations want to achieve the final victory in the battle with the ancient civilization, they must intercept and destroy every ship sent by the ancient civilization outside the cordon, and miss any ship, and the final consequences will be extremely serious.

But to do that, it's really hard!

After all, the number of ships used by ancient civilizations in each war zone is hundreds of millions, and the purpose of such a large-scale ship is to break through the defense line of the cosmic-level civilization and attack the planetary gathering area of the core star field. As a result, it was impossible for the ships of the ancient civilization to come in large formations.

In the process of killing the fleets of ancient civilizations, all the fleets of ancient civilizations must have marched in the form of small formations, and the closer they got to the defense area of the cosmic-level civilization fleet, the more scattered these fleets would be, and the more difficult they would be to capture.

On the vast battlefield, these hundreds of millions of fleets are scattered from all directions, and if they want to find all of them without missing a single miss, successfully intercept all of them, and destroy them all ahead of schedule, such a war really makes people's scalps tingle when they think about it! Because it is really too difficult, and it is so difficult that it cannot be repeated.

You must know that as military faster-than-light warships, their performance in all aspects is quite excellent, the ship's space-time jump ability, conventional curvature navigation ability, or the ship's stealth performance, etc., which are all obstacles to the cosmic-level civilization from carrying out war missions.

It is not difficult to find a large fleet in the starry sky, and it is not difficult to find individual ships for the space-time radar monitoring network of a cosmic-level civilization.

However, the task of locking all the hundreds of millions of military warships in the vast void when the battle situation is unprecedented, constantly carrying out various actions, or making time and space jumps, or sailing with curvature, or concealing and camouflaging in a meteorite state, is also an unprecedented challenge for a cosmic-level civilization.

In a situation where the battlefield is chaotic, and when all kinds of information are mixed and interfere with each other, it is really a difficult task to accurately detect all the hostile ships.

First of all, it is already an extremely difficult thing to ensure that the existence of all hostile ships can be detected in this situation and determine their respective positions, and after the existence of hostile ships is discovered, it is even more difficult to get close to each other, attack each other, and completely destroy the other side.

After all, the ships of ancient civilizations were not chickens waiting to be killed, and they were also powerful war equipment created by cutting-edge technology.

Although the military ships of the ancient civilization are relatively backward in all aspects, and there is a certain generation gap with the ships of the universe-level civilization, in general, the two are still roughly at the same level.

If there is a head-on collision, the ships of the ancient civilization may have to fight several or even a dozen ships to be able to consume a ship of the universe-level civilization, which is all counted from the past battles between the two fleets.

What's more, in this war, the fleets of the ancient civilizations were not fighting to the death with the cosmic-level civilizations. Their goal must be to break through the blockade of the cosmic-level civilization, as long as they can enter the planetary gathering area of the core star field of the cosmic-level civilization alive, they have already achieved the final victory.

At that time, even if these ships of the ancient civilization retreat as soon as they achieve the purpose of the war, it doesn't matter, as long as they can return to the territory of the ancient civilization alive, they will ensure that they will be prosperous and rich for a lifetime, and all of them will have a good life.

Since as long as you can survive to the end, you can get the greatest benefits, it is conceivable that the ships of the ancient civilization will never be stupid enough to fight head-on with the ships of the cosmic-level civilization, they are all able to run and dodge, and do everything possible to hide from the ships of the cosmic-level civilization, and this is precisely the most difficult to deal with.

In the vast void, a ship that can jump in time and space at any time, and can reach several times the speed of light during regular navigation, and even a ship that can be invisible to a certain extent in conventional navigation, is really difficult to catch.

Without the existence of a strong starry sky monitoring network, it is likely that the two ships will be blinded by a certain distance, and the vast void is a place that is more difficult to encounter than the endless deep sea.

Even sometimes you successfully capture the other party's position, and when you work hard to catch up, someone else jumps down in time and space, you still have to be stupid, and then you want to find the other party's position, you have to work hard again, this has to be a cosmic-level civilization to occupy the home advantage, with a strong starry sky monitoring network as a premise, otherwise the other party jumps down a time and space directly is the dragon returning to the sea, where to find?

Within the maximum jump range, people can have endless choices, and can flexibly jump to any position, and after such a space-time jump reaches a certain scale within a certain range, space-time fluctuations will interfere with each other, and there will be further blurred jump landing points, and then these ships will be even more difficult to catch.

Therefore, considering the difficulty of the ships of these ancient civilizations, although the high-level leaders of the cosmic-level civilization drew the final interception and destruction line outside the core star defense boundary within a hundred light-years range, the real main battlefield was obviously impossible to be near this final cordon.

The real battle line must also advance at least two hundred light-years in order to be foolproof, to be able to intercept all targets outside the cordon, and eliminate the threat of ancient civilizations invisibly.

And in order to achieve the difficult combat goal of intercepting and destroying the fleet of the ancient civilization this time, the scale of the combat fleet of the cosmic-level civilization must be even larger, not only the number of ships must not be less, but even dozens of times higher than the number of ships of the ancient civilization.

Because as the attacking side, the ships of the ancient civilization can run around everywhere, but in order to ensure that the ships of the cosmic civilization are invulnerable in the comprehensiveness of interception, they must be fully deployed within the combat area, and a certain fleet must be stationed in each demarcated area.