Nobody cared if Ming He helped the Human Clan. However, when the Cultivation Tribulation ended ,and the Human Clan became the major clan in Untainted Land, every Sage would consider Ming He an eyesore.
Every Sage would want to fight for the Luck of the Human Clan once it became the major clan. When Goddess Nv Wa created human beings, she had primordially occupied 30% of the Human Clan's Luck, while Suiren-Shi, Youchao-Shi, and Ziyi-Shi would get 5% respectively for finding kindling, building houses, and making clothes for the Human Clan.
The remaining 50% of Luck would be the target of every Sage. If Goddess Nv Wa didn't make any effort for the Human Clan, she would get less and less Luck and there would be more left for the other Sages. As for the three Ancestors of the Human Clan: the Suiren-Shi, the Youchao-Shi, and the Ziyin-Shi, their luck would remain only if they didn't do any harm to the Human Clan.
However, Ming He was different. If he helped the Human Clan when they were at the most difficult time, he could naturally get their Luck. The problem was that he needed to create the Ashura Clan and the Ashura Religion soon, which was not suitable for the Human Clan. Therefore, even if he could get the Luck from the Human Clan at this time, he would lose them all later. There was no need to do useless work.
Although Mu Sen was Ming He's Obsession Separation, he was a real human being. Ming He had only separated his obsession and hadn't attached any purusa on Mu Sen, so their relation was very little and even a Sage would find it difficult to find something wrong. Who would consider Ming He's Obsession Separation a human?
Besides, Ming He was a master of the Law of Spiritual Beings so he could easily cover up their relation. Unless Ming He exposed the connection himself later on, or someone had better comprehension than him, nobody would find out about their relationship. Ming He's comprehension of the Law of Spiritual Beings had reached the original stage.
Ming He wouldn't interfere with Mu Sen's decision. Mu Sen wanted to do something for the Human Clan, and Ming He wouldn't stop him. What's more, if he could do something good for the Human Clan, it would be beneficial for his later plans.
In order to protect Mu Sen, Ming He gave him his primordial spiritual treasure, the Wuji Apricot Flag and his mid-grade primordial spiritual treasure, Mount Suppress. Nobody in Untainted Land knew how many treasures Ming He had, so even if someone found these two treasures on Mu Sen, they wouldn't find any relation between him and Ming He.
Mu Sen considered the development of the Human Clan since it had been created. There would be no Way of Celestial Immortality on Earth and human beings would go down the road of technology.
Mu Sen didn't know the relationship between Earth and the Untainted Land, why the Way of Celestial Immortality would disappear, or why there were so many myths about the Untainted Land on Earth. All these mysteries needed time to explain and Mu Sen would be the witness.
These were all stories for later. Currently, the Human Clan was too weak to match with the Wu or Demon Clan. Even a small tribe could eliminate the Human Clan easily. Although the three Ancestors of the Human Clan could partly enhance their force, they were just drops in the bucket in Untainted Land.
Therefore, the Human Clan could only be a major force in the Untainted Land if their entire force was enhanced. However, which way should they choose? The Way of Celestial Immortality? Mu Sen ruled this out it after rethinking about it. If the Human Clan chose the Way of Celestial Immortality, Ming He could provide them with a lot of tactics. Although many of his tactics weren't suitable for the Human Clan, Ming He could easily predict some improved tactics for them by the time he reached his peak stage of Sage-to-be.
However, Mu Sen still worried about whether the Way of Celestial Immortality was suitable for the Human Clan. The Way of Celestial Immortality would disappear from the Earth later. What's more, the cultivation of Immortality needed plenty of spiritual treasures and weapons, but they didn't have that many. How could they compare with the other clans who had collected these treasures for such a long time?
Besides, although the Human Clan would become the major clan in the Untainted Land at the end of the Cultivation Tribulation, at this time, they were still under control of the Sages. The religions of Sages had already cultivated on the Way of Celestial Immortality for such a long time. Therefore, there would be no possibility for the Human Clan to become stronger than the other clans if they chose to cultivate the Way of Celestial Immortality.
In the long-term, even if the Three Royals and Five Emperors  got enormous Merits, they were enough for them to reach the stage of Sage-to-be, but where would they be in the end? And they would be pressed in the Fire Clouds Cave years later. If there were eight martial cultivators at a similar stage of Sage-to-be and they were the Royals and Emperors, even Sages couldn't bother them directly. After all, eight cultivators at the stage of Sage-to-be would have incredible power.
Besides, the Three Ancestors of the Human Clan had disappeared since the age of Three Royals and Five Emperors began. Nobody knew where they were. Maybe they were also in a serious situation. Therefore, if the Human Clan chose to cultivate the Way of Celestial Immortality, would they really become the major clan in Untainted Land?
These days, the Wu and Demon Clans were fighting against each other. Owing to the strong force of the two clans, the Sage Hong Jun wouldn't directly interfere in the war between them. If the Human Clan could have that kind of force, they wouldn't be afraid of Sages anymore. If the Sages did anything harmful to the Human Clan, the humans wouldn't follow any of the religions that the Sages had built.
Because of their weakness, the Human Clan was under the control of the Sage. Mu Sen hoped his clan could get rid of any control from others, including Sages. He believed he wouldn't yield to his fate since he had been reborn. He knew that the Human Clan must follow their own way of Tao, not the Way of Celestial Immortality otherwise they would become the puppets of the Sages later.
Therefore, Mu Sen chose Martial Arts as their Tao. Not only would it be affected by some novels about martial arts in the later world, but also, he realized that there would still be some martial cultivators after thousands of years. The Way of Dao would be more suitable for the Human Clan than the Way of Celestial Immortality.
Thinking of this, Mu Sen immediately got in contact with Ming He who was staying in the Blood Sea. Understanding Mu Sen's idea, Ming He agreed with him completely. The Way of Martial Arts was nice indeed. He started to predict cultivation methods of Martial Arts through his Magical Tao Mirror and then delivered all he had predicted to Mu Sen.
While Ming He predicted the methods, Mu Sen was cultivating. By the time Ming He finished his prediction Mu Sen had ascended the stage of Da Luo Golden Immortal. Then, they prayed for the Way of Heaven and set the Spiritual Inheritance of Martial Arts for the Human Clan. Naturally, Merits fell down from the Heaven because they had done something beneficial for the Human Clan. To their surprise, a Taoism character "Wu" also showed up in the sky.
Taoism characters, which the Hundred Clans knew clearly, were not rare in Untainted Land. However, this Taoism character "Wu" awarded by the Way of Heaven had never shown up in the Untainted Land. Besides, the "Wu" character was not simply a Taoism character. It contained the Law of Martial Arts and the Way of Martial Arts. If someone could predict it long-term, his cultivation of Martial Arts would be really powerful.
As for the Merits, Mu Sen hadn't decided where to use them, so he stored them temporarily in the "Wu" character. Mu Sen had planned to integrate these Merits into the "Wu", but this character was different from spiritual treasures which could absorb the Merits to enhance their power. Therefore, Mu Sen could only store the Merits in it for a while.
After that, Mu Sen started his 49-year teaching of Martial Arts to the Human Clan, from the basic Martial Student to the stage of Heaven Clashing (the stage similar to Da Luo Golden Immortal). As for the higher stages of Fate Reading and the Martial Sage, he didn't plan to mention these in this teaching. As a cultivator at Da Luo Golden Immortal, Mu Sen shouldn't have had the ability to predict out the complete Law and Way of Martial Arts by himself. He didn't want others to know his secret.
After finishing his teaching, Mu Sen started his Closed Door Meditation and tried his best to comprehend the "Wu" character. Meanwhile, the three Ancestors of the Human Clan knew that the Way of Celestial Immortality would have both benefits and disadvantages for the Human Clan, and they hoped their clan would not be controlled by the others. Therefore, they chose to trust Mu Sen and started to cultivate the Martial Arts. They needed to enhance their force at once with the Spiritual Inheritance of the Martial Arts to protect their clan.
After a very short hundred years, the Human Clan became much stronger than before. With the Law and Way of Martial Arts, plenty of martial talents were showing up in the Human Clan. Most of them had already reached the stages of Martial Mentor or Martial General, and some outstanding talents had even broken through the stage of Martial Supreme (also known as the Black Immortal). The abundance of spiritual air and treasures from heaven and earth played an important role. In years to come, it wouldn't be as important as it was now.
The three Ancestors of the Human Clan cultivated the Martial Arts more easily since they were actually at the stage of Da Luo Golden Immortal and could constantly absorb the Luck of the Human Clan. During these years, they ascended the stage of Heaven Clashing, which was equal to the Da Luo Golden Immortal. Although they were just at the early stage of Heaven Clashing, they were far more powerful than before.