However, Cui Si didn't just have three or five top-level flying boats in his hands! There are more than a dozen of them, and there are nearly three hundred secondary Shenzhou that can also absorb the aura of heaven and earth to fight. With such a large number of fleets, if they desperately absorbed the aura of heaven and earth together during the great war, it would be a very terrifying demand, and even the low-level spirit realm could not guarantee the supply. Even the spiritual realm, which is rich in spiritual energy, cannot support such a large amount of consumption for a long time.

And once a large number of heaven and earth aura in the spirit world disappears, not only Cui Si's fleet will become useless waste in the future, but it will also have disastrous consequences for the entire spirit world, maybe all the living beings in it will be killed, and it will completely become a barren land.

Cui Si is not a murderer, of course he can't allow such a thing to happen. And he may also fight in special realms, such as the Nine Hells and the Endless Depths, where the aura of heaven and earth itself is very meager, but the evil qi and demonic qi are abundant. If you still want to rely on absorbing the aura of heaven and earth to fight, then you will inevitably suffer a big loss.

So as soon as this problem appeared, it immediately attracted Cui Si's attention. After nearly 100 years of research, Cui Si finally reluctantly solved this problem through two improvements.

One of Cui Si's solutions was to change the way the Five Spell Flying Boat replenished its aura. In addition to exposing their ability to absorb the aura of heaven and earth on their own, it also allows them to absorb the five spells in reserve as power.

After all, these flying boats are all refined with five spells, and they do not reject the five spells of the same origin and root at all, and with a slight change, they can transform the small balls of the same attribute into their own aura. It's the same as using spirit stones to replenish aura, but the spirit stones with thin aura are replaced with small balls with huge aura.

In this way, as long as Cui Si reserves enough five spells in the Five Spell Flying Boat in advance, he can use small balls to replenish the aura when he can't absorb the Heaven and Earth Spiritual Qi supplement, so that the Five Spell Flying Boat can continue to fight.

Anyway, for Cui Si, there are so many subordinate condensation balls, there is no shortage of this thing at all, plus there is enough storage space in the Five Spell Flying Boat, there is no problem in storing the mountains, let alone the small balls!

As a result, Cui Si, who had a lot of money, let each five-spell flying boat store a small ball reserve that was enough for the flying boat itself to use in continuous combat for a month. With these small ball reserves, even in a space without the aura of heaven and earth, Cui Si could make his five-spell flying boat fleet exert its tremendous combat effectiveness.

In addition to this improvement, Cui Si also deliberately improved the five-spell launcher. In the past, the Five Spell Towers were installed on the flying ships as their main weapons. The Five Spell Tower can absorb enough aura from the flying boat, condense it into a small ball, and then automatically aim and launch it. If you want to say convenient, it is really convenient, you can attack automatically without people looking at it.

However, the consumption of the Five Spell Towers is too terrifying, this consumption is mainly reflected in two aspects, one is that the Five Spell Towers themselves are expensive, accounting for almost one-third of the total cost of the flying boat, or even more, and the other is that the Five Spell Towers consume too much aura.

Because the five spells launched by the Five Spell Tower are all made on the spot, then in the process of absorbing the aura and condensing the small ball, it is inevitable to waste a lot of aura. The amount of aura wasted is related to the Five Spell Towers themselves, the high-level Five Spell Towers waste less aura, and the condensation time is fast, while the low-level ones are the opposite.

However, even the highest-level Five Spell Towers would have to waste half of their aura in the process of condensing the Five Spells, and its cost would almost be comparable to that of a high-grade Spirit Treasure.

In this regard, Cui Si said that he was under a lot of pressure and always wanted to improve, but he didn't know where to start, until one day, he accidentally discovered a treasure he had obtained when he was young, which inspired him and found a solution.

The treasure that Cui Si found was the Dragon Head Sky Cannon, when he was a congenital monk, he was chased and killed by four foundation building monks, and one of the guys used this Dragon Head Sky Cannon, with the Earth Fire Five Spells to bombard Cui Si. If it weren't for the big bell, a hundred Cui Si would have died. That was the closest Cui Si came to death, and he himself was a little scared when he thought about it now.

And after this dragon-headed bombardment cannon was captured by Cui Si, it was kept by him as a trophy. It wasn't until that day that on a whim, turning over what he had before, that he found it out again.

After seeing this dragon's head bombarding the sky, Cui Si's eyes suddenly lit up. The Dragon Head Bombardment Cannon itself can already be regarded as a low-level thing for Cui Si, but it has given Cui Si a new enlightenment.

Because the principle of this dragon's head bombardment cannon is completely different from the principle of the five spells released by the cultivation realm, the five spell tower of the cultivation realm is to condense the five spells by oneself and then throw them out. However, the Dragon's Head Bombardment Cannon was made in advance after the five spells were made, and then shot out when they were used.

Don't look at this little difference, when it comes to using it, it is a world of difference. The Five Spells Tower, which condenses the Five Spells, consumes the aura of the Shenzhou itself, and the aura of the Shenzhou itself still needs to fly and defend, which is not much, and it is even more stretched when it is consumed by the Five Spells Tower.

The top-level flying boat has almost infinite aura, and he doesn't care, but after Cui Si forms the Shenzhou fleet, it is impossible to have endless aura, so this consumption is huge.

And if the Five Spell Towers were replaced with the Dragon's Head Bombardment Cannon, it would be completely different. The Dragon's Head Bombardment Cannon only consumes a little bit of its own aura, which can be used to aim and fire. The five spells it needs can be accumulated in normal times, and this time it saves a lot of aura from the Five Spell Flying Boat, allowing it to engage in more protracted battles!

Cui Si quickly figured these things out, and then began to collect refining methods for treasures like the Dragon's Head Bombardment Cannon.

With Cui Si's financial resources and power, of course, it was not a problem to collect these things, and then coupled with the ingenuity of Xue Jing and others, after spending decades of time, the new treasure "Five Spells Dragon Pattern Cannon" was born.

The five-spell dragon pattern cannon varies from three zhang to thirty zhang in length according to the need, and it is carved with exquisite dragon patterns, which is extremely gorgeous.

As of a few days ago, Cui Si only built two varieties of five-spell dragon pattern cannons made of earth-based half-immortal family five-spell refining, and five-spell dragon pattern cannons made of wood-based five-spell refining, and installed them on the two major types of five-spell flying boats under his hands.