Qiu Chengfeng was busy setting up defenses, while Ouyang Mu was busy rushing back to the sect, and Zhang Yu stayed here in the Lingshi vein for the time being, staying with Zhou Fat'er and the others.

Zhou Fat'er learned how to measure the content of ore veins from Ouyang Mu, and took Wang Chensheng and a few people to work in the mine every day.

Zhang Yu went to patrol the surrounding defenses, arranged camouflage, and spent the rest of his time cultivating on the spirit stone veins, he opened the system at this time and was ready to try to upgrade the life and death decision, he put in a soldier-level crystal and soul value, and clicked the upgrade button.

At the moment when he clicked the upgrade button, he felt a huge force pouring down from the Baihui acupoint above his head, and another force went straight up from the perineum, one hot and one cold, one yin and one yang, like a dragon and a phoenix intersecting, they were in the body of the dantian round, and then circulated the major acupoints of the human body, entangled with each other.

At this moment, the cultivators patrolling around the spiritual stone veins all felt the changes in heaven and earth, as if there was some attraction, and they kept absorbing the surrounding spiritual energy rotation.

They all gathered in the center, and unexpectedly found that the place where the aura gathered was actually Zhang Yu's residence.

At this time, Zhou Fat'er also rushed over, and when he saw this scene, his eyes lit up and shouted: "It must be the boss who is practicing......"

Everyone's eyes were also bright, and they all became excited, the stronger Zhang Yu was, the stronger they were, and they didn't know what exercises could actually cause changes in heaven and earth.

"What are you doing here, what should you do!" Qiu Chengfeng also rushed here, and couldn't help shouting when he saw everyone talking.

"Let's go, let's go!" Everyone was afraid of Qiu Chengfeng, and immediately dispersed, leaving only Lin Xie, Zhou Fat'er and Wang Chensheng here.

"What the hell is the boss doing?" Qiu Chengfeng leaned over and asked.

"You don't know what you're looking at!" Lin Xie rolled his eyes, turned around and left with a cold and arrogant expression.

Zhang Yu didn't know what was going on outside, because the two gases merged together and began to march towards the dantian, to Zhang Yu's surprise, the two dantians in the dantian began to rotate, and the scene was particularly strange, like two lively fish playing, one big and one small, and the small one was the dantian that was transformed into a life and death decision.

In the process of spinning and playing, the small fish poured in with the two air currents, and it actually got bigger and bigger, and at the moment when the two air currents poured in, Zhang Yu felt that the dantian flashed with golden light, and a tearing feeling made him feel painful.

Sweat kept leaving from his forehead, Zhang Yu's unyielding personality was revealed, and he gritted his teeth and endured it.

I don't know how long it took, the airflow that made the dantian tear disappeared without a trace, and was replaced by a cool meaning rising from the dantian, this cool cycle turned into the whole body, making Zhang Yu feel as if he was soaked in hot water, and he didn't want to move.

It took him a long time to react, and then he looked inwardly at the dantian, and sure enough, he found that there were two qi seas in the dantian that looked like a taiji diagram, and a pair of yin and yang and two fish appeared in the two qi seas?

What does this mean? Could it be that he has mutated after learning life and death? Zhang Yu was puzzled, and after studying for a while, he realized that the Taijitu-like dantian contained twice the amount of aura than the enemy of the same level, which meant that his moves were also doubled.

The two dantian yin and yang formed a Taiji diagram by mistake, automatically absorbing aura from all around, and pushing the yin and yang two fish to rotate, which means that even if Zhang Yu does not deliberately practice, the yin and yang two fish are automatically rotating.

Zhang Yu was overjoyed in his heart, and secretly calculated the rotation time of the two fish of yin and yang, and found that it would take a few months at most from the second to the third layer of the foundation building period, of course, if he kept squatting in the spirit stone mine cave, this time would be shortened.

Thinking of the time, Zhang Yu couldn't help but sigh secretly, not knowing what happened to that world, grandfather and daughters.

It's a pity that he can only think about it, Zhang Yu opened the system and looked at it, the life and death decision on the skill panel became the second layer, and upgrading to the third layer required a level crystal nucleus, as well as a massive amount of soul value, seeing that series of zeros, Zhang Yu had a headache.

What surprised him even more was that the life and death decision was upgraded to the second layer, and the text in the life and death decision was completed a little, Zhang Yu took a closer look, and found that the life and death decision also talked about many ways to strengthen the body, divided into skin refining, meat refining, and bone refining, the scroll information was not comprehensive, and the content was missing later.

Refining skin is relatively simple, it is nothing more than using foreign objects to strike, and there are several methods introduced above......

Zhang Yu stayed underground for a month, exercising and practicing exercises every day. During this month, the basic defense and illusion arrays were arranged, and as long as they were not cultivators in the foundation building period, they would definitely not find anything abnormal here.

There were also many people in the Black Castle, they built simple defenses, large pieces of spirit stones were excavated, they were enclosed in the formation, and transported back to the Lantian Transit Station, no, Lantian Castle was processed.

Since the sect decided to abandon the Black Castle, countless materials have been transported to the transit station, a city is being built, and they have decided to mine the newly developed ore veins on a large scale.

The Dan Dao Sect did not know that there was a larger vein in the location of the Black Castle. Zhou Fat'er spent a month simply measuring the ore vein, and the number he got made Zhang Yu a little dizzy, this ore vein went straight to the ground I don't know how deep, and the spirit stone content was enough to support the Dan Dao sect to become the most powerful sect among the four sects.

It's a pity that only part of this vein is on the third layer, and you have to go down another layer to dig it, and you have to wait until later to think about the terrifying creatures below.

Ouyang Mu finally came back, he casually found a reason to bring a large amount of supplies, and there were more than twenty Qi Refining Stage cultivators who came with him, these were the elite forces of the Ouyang family.

In order to convince the family elders, Ouyang Mu tried his best to speak, the huge profits of the spirit stone vein were eye-catching, compared to the sect, the Xiuzhen family first considered the interests of the family, since they decided to support Zhang Yu, then they naturally fully supported it.

A large number of supplies made this place much better, and at Ouyang Mu's request, these cultivators immediately put into cleaning and building after putting fire marks on their foreheads. vaguely competed with Qiu Chengfeng, and the efficiency of the two sides was strengthened all of a sudden, and Zhang Yu was happy to see this scene.

As for the matter of the Heavenly Master Clan, Ouyang Mu also inquired, it is said that when the Holy Dao Heavenly Master Zhang Sanfeng died, the Heavenly Master Clan was divided into several branches, in addition to one that disappeared without a trace, there was also one that was sealed in a certain space......

Zhang Yu was stunned, the one who disappeared must have gone to the earth, where is the seal? Zhang Yu sighed, at least it is good to have a clue.

At the same time, Ouyang Mu also brought a manuscript of the Dark River map, and Zhang Yu quickly called a meeting of several people to study the manuscript map together.

"This is the map of the Dark River?" Zhang Yu looked at the dense, distorted lines on the manuscript, which could not be connected with the Dark River.

"Yes, this is indeed the Dark River, this was found by chance by a senior of the Ouyang family decades ago, he was proficient in mathematics, and he had the courage to sneak in from the Dark River and get out of the Qiushui Lake. This incident was recorded in a manuscript and put in the family files, and I only occasionally looked through it. Ouyang Mu said with a smile.

"What do you think of this?" Zhou Fat'er is very concerned about this matter, it is related to his business plan, if he can really cross to Qiushui Lake, he can transport these spirit stones out, and then earn countless resources, pills, and magic weapons.

It's a pity that everyone present studied it and was at a loss for this map, Zhang Yu turned his head and asked, "How do you explain this?"

"I also don't know much about it, you see that these lines are divided into several colors, and each color must represent meaning, but why did the predecessors draw so many irregular circles?" Ouyang Mu said with a wry smile.

"Could it be such a ......"