Mu Sen did not completely spread the Way of Celestial Immortality among the Human Clan. Martial and celestial cultivators in Sacred Island of Spiritual Inheritence could freely come and comprehend these Enlightenment Tablets, but outside it, only basic transforming exercises were available. This was meant to leave humans a firm cultivation foundation.
Martial and celestial cultivators of the Human Clan who were away could enter Sacred Land to cultivate after reaching the stage of Earth Changing (Taiyi Black Immortal). It did not matter whether they had gone through the selection process. This would allow the gathering of the elites of the clan. This way, even if the clan suffered a misfortune, they could still conserve their force.
Besides, they had also discovered a human flaw. The body condition of humans was gradually deteriorating from generation to generation. Even if their population rapidly increased, fewer and fewer cultivators were able to pass the selection.
The most important aspect of achieving the Way of Celestial Immortality was the inherent nature of the cultivator. If things continued this way, there would be fewer cultivators and many more ordinary humans. The cultivation of Martial Arts was different. It emphasized on persistence, with body condition and comprehension being the least important factors. If a human persevered in practicing, there would at least be some progress. If he had a little perception and given opportunities, he would succeed in the end.
In the next thousand years, Sacred Land of Spiritual Inheritance expanded endlessly. A selection was held every decade. Though fewer cultivators passed the selection, there were often great talents who showed up. Among the growing number of humans, even just one talent was sufficient for the development of the Human Clan.
The Human Clan became formidable after developing over a peaceful millennium. Not only was the force inside the sacred land greatly enhanced, but so was the force outside. No one could underestimate the force of the clan anymore. The clan was full of Martial Supremes or Black Immortals. Some human tribes leaders had even reached the stage of Heaven Changing or Golden Immortal.
With the spread of Martial Arts and the Way of Celestial Immortality among humans, their strength was greatly enhanced. In just a millennium, their population increased from 10 million to 10 billion. This left the other creatures in Untainted Land completely shocked.
Coast of the East Sea was no longer enough enough to accommodate the rising number of humans so the clan had to expand their territory to the mainland of Untainted Land. Untainted Land was so vast and boundless that not even the ruler of this land, the Wu Clan, could occupy the whole land. The Wu Clan merely chose to develop in better parts of the land, while the rest were mostly occupied by the Demon Clan.
With fewer treasures for cultivation and under the pressure of Wu Clan, the Demon Clan in Untainted Land was different from that in Heavenly Court. What was worse, the tribes within the clan would fight against each other for profits. And at this time, the expansion of the Human Clan into Untainted Land stressed them even more so.
When Emperor Jun first migrated to Heavenly Court, he brought most of his Demon Clan with him, leaving behind only some weaker demons. Facing the persecution of the Wu Clan, they became weaker and weaker. They were now even worse than some tribes of the Human Clan. Fragmented, they scattered in every corner of the land and had no strength to resist the Human Clan expansion.
Three Ancestors of the Human Clan were delighted about their clan's expansion, since it was what they had hoped for. Even without their three ancestors, the clan now had enough power to fight against the Demon Clan.
Mu Sen was also happy to see the development of his clan, but he still worried about the dangers that his clan would face. What they were fighting against was just the Demon Clan in Untainted Land, which was abandoned by those in Heavenly Court. Under the suppression of the Wu Clan, the so-called Demon Clan did not have actually have a powerful force.
If the clan in Heavenly Court waged a war against his clan some day, humans would have no power to resist. However, the Human Clan expansion was necessary, since Coast of the East Sea could not hold any more humans.
Mu Sen worried if humans would survive to return to Coast of the East Sea after leaving. However, he could not stop them as the clan needed to challenge themselves without his protection.
Fortunately, Sacred Land of Spiritual Inheritance witnessed a smooth advancement. With abundant resources for cultivation, the Spiritual Inheritance of Sacred Palace, and Mu Sen's Teachings, this land fostered plenty of talents and elites. The speed of development in Sacred Land was far faster compared to the outside.
In the nearly 1,100 years since Sacred Land of Spiritual Inheritance was built, the Human Clan had recruited more than 10 million humans. Compared to the humans outside, they were superior in every aspect. The clan was full of Martial Supremes and Black Immortals. Cultivators at the stage of Heaven Changing or Golden Immortal were an ordinary sight. Some outstanding talents had even reached the stage of Heavenly Signs Changing or Taiyi Golden Immortal.
Of course, there were also several excellent cultivators whose talent in cultivation amazed even Mu Sen. One of then was Wu Chen, who was also in the first batch of humans created by Goddess Nv Wa. In just 2,000 years, he had reached the stage of Heaven Clashing. He was the first person to realize his Dao of Origin, except for the four Ancestors of Human Clan.
Wu Chen cultivated the sword part of Martial Arts and his Way of Martial Arts was a sword. When he ascended the stage of Heaven Clashing, he had comprehended the Law of Void which had some connection with the Law of Space. Later on, Wu Chen created the Void Swordsmanship himself. Walking in the void and moving like wind, he could kill his enemies in the span of a breath and could be considered the best swordsman in the clan.
In fact, Mu Sen really wanted to take Wu Chen as his disciple. However, he knew Wu Chen had found his own Way of Dao, so it seemed there was little he could teach him. Since it was so, he hoped Wu Chen could continue on his own way. Perhaps Wu Chen would become a key figure to support the Human Clan some day.
The reason why Sacred Land of Spiritual Inheritance could develop so rapidly was because Mu Sen asked Ming He for half of his treasures to support his Human Clan. Though most of these treasures were at the mid or low level, they were essential to their clan's development. Mu Sen would not tell the others where these treasures came from. He told them he received them from the master who refined the 3,600 Enlightenment Tablets. To be fair, he did not lie.
Part of Ming He's treasures he received were materials for weapon-refining. Weapons and spiritual treasures were indispensable for cultivators of Martial Arts and the Way of Celestial Immortality after all. Though most of these materials were meant to refine post-celestial spiritual treasures, it was enough for humans. It had actually been great to refine those treasures since many of what they had refined did not even reach the post-celestial level.
The rest were treasures from heaven and earth or spiritual roots and trees. Mu Sen specially asked for the Spiritual Map of the Living refined by Ming He when he first traveled around Untainted Land. In fact, the map used to be a Mid Grade Postcelestial Spiritual Treasure. Before he gave it to Mu Sen, Ming He refined the map once again by adding more materials and broken pieces of Primordial Spiritual Treasures from his collection when he battled the 68 Sages-to-be.
Therefore, the new Spiritual Map of the Living had become a Mid Grade Primordial Spiritual Treasure, with a space ten times large inside. Mu Sen put all the treasures he got into this Map and continued producing more useful resources for the advancement of his clan.
The other treasures from Ming He were the 23 Primordial Spiritual Treasures. 22 were the Low Grade Primordial Spiritual Treasure. They were all collected by Ming He from his battle with the 68 Sages-to-be. He did not have any particular use for them, so he gave them all for Mu Sen to enhance the force of the Human Clan.
The three Ancestors of Human Clan owned one Postcelestial Merit Spiritual Treasure respectively. Therefore, Mu Sen gave each of them a Primordial Spiritual Treasure. As for Wu Chen, Mu Sen sent him a sword which an attacking power that was considered good among the Low Grade Primordial Spiritual Treasures. Working in with his Void Swordsmanship, this sword could give out an amazing power.
The last Primordial Spiritual Treasure was a Top Grade Primordial Spiritual Treasure with space quality, named the Spiritual Mirror. Ming He found this treasure after killing Ancestor of Wild Wind. Mu Sen also put some Ominous Beasts (raised by Ming He for the Shura Clan) inside the mirror, so that it would be a place for human cultivators to do their real killing exercises.
The Spiritual Mirror would open once a century. When it was open, Mu Sen would put enormous treasures of cultivation inside. All humans were free to go inside to train. Naturally, the mirror was a place full of danger and the Omnious Beasts would be at different levels, some even reaching Da Luo Immortal. Each time it was open, many humans would perish inside.
However, long-time cultivation could not always enhance their power. They could only become much stronger by experiencing life-and-death battles. This was also the real purpose for Mu Sen to set up this training space inside the Spiritual Mirror. Though it was a pity that some great talents and elites died there, many more strong cultivators were born. This was so-called lose and gain.