Lu Yu originally thought that it would be more than enough to exchange one million contribution points for the next cultivation textbooks, but after he really started exchanging, Lu Yu found that it was difficult to say whether these contribution points were enough or not.

"Level 4 Perfect Growth Tutorial, you will be charged 250,000 points for contributions, welcome to visit next time. ”

After hearing this voice, Lu Yu thought that his current stage of exchange had been completed, but after obtaining this skill, there were many auxiliary textbooks such as "Basic Combat Skills of Level 4 Energy Creatures", "Physical Enhancement of Level 4 Energy Creatures", and "Primitive War Science" on the exchange list.

Each of these textbooks costs tens of thousands of contribution points, and many of them are red.

Lu Yu remembered that the system deity said that if he wanted to build a perfect foundation at this stage, he had to exchange all the auxiliary teaching materials that could be exchanged.

But many of these textbooks still can't be exchanged, some textbooks require the proficiency of the main tutorial to reach a certain value, and more textbooks need to learn other textbooks in addition to the proficiency requirements, so that one million contribution points is really not enough.

"Poor. Lu Yu sighed helplessly, and while secretly scolding the insatiable greed in the system world, he had a deeper understanding of knowledge is productivity.

Lu Yu originally wanted to convert the excess energy into proficiency before entering the next secret realm, but after taking a look, he found that the national teachers were so tired that he trembled, and immediately dispelled this idea, in case he couldn't stand it, and the thirty-six demon of the cultivation period broke in, where could Lu Yu reason?

Then, Lu Yu released the Divine Thoughts Force one step ahead.

"National Teacher, which secret realm gives you the most pressure? He followed the eyes of the national teacher to the front of the entrance, and at the same time, the cultivators who followed him last time also consciously ran behind him.

Seeing that these explosive bombs were so good, Lu Yu nodded, without them, he really didn't dare to say that he could defeat the Cultivating God Demon.

After gesturing to the national teacher, Lu Yu's Divine Thought team entered the secret realm with the flock of birds, and the others followed Lu Yu to break in.

At the same time, the national teacher exhaled deeply, without this pressure, he could still support for a few more hours.

The scene of the secret realm was the same as the last time, and the empty world was covered with endless ashes.

This time, no one dared to move again, Lu Yu directly unfolded the protective wall, and all the people hid much farther away from the edge of the protective wall, the last time the scene when the protective wall was reduced by the cultivation period was attacked and killed by the evil demons, they will never forget it in their lives.

In the next moment, everyone released their own army of divine thoughts, and only in this way could they reduce Lu Yu's pressure to the greatest extent.

Everyone didn't look at the ashes anymore, their eyes were wandering in the air, and the memories of the last time told them that the Cultivator Demon was in the air, but now they couldn't find it.

"Human, why are you aware of my location?" At this moment, the young and melodious child's voice came to everyone's ears, and the rainbow butterfly wings appeared without warning, and the little boy with pink carving, giggling, flew and danced in the air.

But this extremely beautiful figure could no longer make a trace of appreciation rise in the hearts of everyone, and in their hearts, there was only boundless hatred and fear of death.

Then, everyone's eyes focused on Lu Yu.

"You fight the birds with all your might, and I'll find a way to deal with the demons in the air. As he spoke, he also released all of his Divine Beings.

As soon as these divine creatures appeared in reality, they forgot about themselves, and they became warriors who were not afraid of death.

"Human, you're funny. The little boy glanced at Lu Yu's Divine Thoughts Force, and a trace of surprise flashed in his eyes, but he was not afraid, such strength was far from threatening him.

"Attack with all your might!" After giving this order to his own Divine Thought Creature, Lu Yu sneaked his consciousness into the Divine Thought World and began the next cultivation.

The situation on the battlefield is not optimistic, the human troops are unable to move an inch under the onslaught of the birds, and all long-range attacks will be easily dodged by the demons in the air.

But some humans are not panicking, and in their opinion, this demon is likely to explode inexplicably, as long as they can persevere.

And just when the two sides were fighting, Lu Yu's energy was all focused on the teaching materials.

The content of the textbook is basically divided into two lines, biology and science and technology.

The biology chapter is about creating all kinds of creatures that are strong or have some value to the world.

The chapter of science and technology is to strengthen the mode of production, cultivation mode, tool strengthening, civilization system and other aspects of human beings.

The two are alternate, and in Lu Yu's opinion, there must be a very reasonable reason for this order of arrangement.

But time was pressing, and Lu Yu could only use his energy on the teaching materials as soon as possible.

"Level 4 Perfect Growth Tutorial with a proficiency level of 1/100. ”

At the beginning, Lu Yu came into contact with the biology chapter, but unlike the imitation of the innate stage, the creatures he learned this time slowly appeared as the conditions changed.

Under Lu Yu's thought for a hundred years, in various natural environments that are at a certain distance from the human city, all kinds of strong or valuable creatures gradually appeared, they fought each other at first, fighting for territory, but they soon found that in the distance, there was a group of tender and delicious but very weak human beings, so the human beings who had been standing at the top of Lu Yu's divine space were no longer top.

Over the course of a hundred years, the number of other creatures has gradually increased, while humans have struggled, but they have also gradually decreased.

In this process, the weak humans died, but the strong humans who could compete with the beasts survived, and Lu Yu realized that this process was a cruel and effective distribution method chosen by the Divine Mind Space in the case of limited energy.

At the same time, the battle situation outside had also changed dramatically, and in the frightened eyes of everyone, Lu Yu's huge army of divine thoughts suddenly decreased a lot.

"Could it be that Lu Yu can't stand it?" Everyone was bloodless, although they were all in the cultivation period, but they knew very well that whether they could survive or not, whether the emperor could continue to exist, it all depended on Lu Yu alone.

"Something is wrong...... the demon in the air found an abnormality, he could feel that the disappearance of this human divine creature was not because it could not withstand his own attack, on the contrary, what was this human being doing, but he was not panicking, no matter what Lu Yu did, in his eyes, it was a futile struggle.

After a few breaths, a group of powerful beasts appeared on the battlefield, although their number was much lower than that of the newly disappeared army of divine thoughts, but they gave people the impression that they were much stronger than them.

They roared and rushed towards the unstoppable flock of golden birds...... 2k reading web