Solar Immortal Physique was one of the twelve Immortal Physiques; no one in this world could be born with an Immortal Physique. Immortal Emperor Min Ren's Solar Immortal Physique was from the Physique Scripture currently within the hands of Li Qiye.
Li Qiye knew that the Physique Scripture was craved by all, so he had it hidden. He was also afraid that he would lose it one day. He had to find a way to preserve it since his memories regarding it would be erased so that the Demon Heaven Grotto wouldn't get it.
In preparation for that day, he hid the mysterious truths of the Physique Scripture in the martial arts manuals that all cultivators look down upon. He separated it into three parts, hid them in three different types of martial arts manuals, spanning one hundred and twenty manuals containing ten thousand different techniques.
Li Qiye used a particular order that only he knew about to hide them in the manuals, so, even if someone knew where it was, they wouldn't be able to piece it together.
At that time, he separated the three types of martial arts into three different eras, so they had no relation with each other.
Within these three eras, he mass produced and separated them everywhere in all of the Nine Worlds, not just the Mortal Emperor World. There were at least a hundred thousand copies in each world.
With the help of the other Immortal Emperors and the Alchemy God, although he erased his memories of the techniques, the order of these martial arts manuals remained. From the past until now, no cultivator had read all one hundred and twenty manuals.
Li Qiye purposely left all one hundred and twenty manuals in the Cleansing Incense Ancient Sect so, if a disciple was able to discern this secret, he would be able to cultivate an Immortal Physique. Maybe then, the sect would have another Immortal Emperor or at least, a Virtuous Paragon with an Immortal Physique.
Unfortunately, no one would even look at these manuals, let alone taking the time to research them. This was why after Min Ren, there was no second person with an Immortal Physique.
Li Qiye spent the whole night copying the Physique Scripture from the manuals. After reading what he wrote, Li Qi ye couldn't help but satisfyingly smile. As he read each word, his lost memories of the Scripture slowly appeared in his mind. Eventually, the entirety of the Scripture had been completed.
After remembering the whole thing, he burned his written copy. He knew the value of the Physique Scripture. If someone knew that he was in possession of it, there would be a calamity to endure. He could only hide it in his head.
The truth was that the original Physique Scripture had been hidden by Li Qiye, and no one else in the world knew where it was. However, Li Qiye was not in a hurry to get it because the Scriptures were also related to another secret; they weren't just cultivational techniques. Afterward, Li Qiye rested for a little bit before the morning. Nan Huairen came early to the peak to meet Li Qiye.
"Senior, I'm afraid I can't go with you to the Weapon Armory today. The Elders told me to go report the events regarding the marriage to the Sect Master; I have to leave the sect." Nan Huairen said.
Nan Huairen was valued by the Elders for his intelligence, so he was given an important mission.
"Go; I'm not in a rush for a weapon." Li Qiye nodded slightly, he wanted to use this time to reorganize the techniques and methods inside his mind.
After Nan Huairen left, Li Qiye didn't continue sleeping. He took out the Kun Peng's Minor Sixth Form manual. It was highly regarded by the third generation disciples because it was still part of an Emperor merit law.
Each Immortal Emperor had always created formidable merit laws. Some were longevity cultivation methods that could increase one life's span and blood energy. Others were Fate Palace techniques meant for offensive and defensive potentials. Last were the different ways to strengthen one's Physique. These three were the general types of merit laws that were crafted by Immortal Emperors; they also included Heaven's Will Secret Laws.
In his life, Min Ren had founded many different Emperor manuals, and Li Qiye was familiar with them; after all, he participated in the formation of these manuals.
During his last hibernation, his memories were erased by the Black Dragon King of Heaven Protector City, but he could still regain them.
Kun Peng's Minor Sixth Form was a subsidiary of the Emperor Merit Law "Kun Peng's Six Variants". It was the strongest Fate Palace Merit Law created by Min Ren.
Right now, Li Qiye didn't have access to the high-level Emperor merit laws in the Cleansing Incense Ancient Sect, so he didn't know if the Six Variants was still available. However, he could use the minor sixth form to regain his old memories regarding the actual Six Variants.
Slowly reading the minor sixth form, Li Qiye found that the manual only had six simple movements, not enough to be considered a legitimate Emperor merit law. But the Six Variants were derived from these six simple actions.
Li Qiye, in the past, had brought Min Ren to watch a Kun Peng from far away. Min Ren's observation eventually turned into six basic movements, and they were used to create the infamous Emperor Fate Law – Kun Peng's Six Variants.
The six actions slowly appeared in Li Qiye's head. Sometimes it was an eagle flying in the nine firmaments where a single flap of its wings would take it three thousand miles away. Another was a fast descent into the ground with enough force to pierce through the layers of hell. The third was in the depths of the sea; it transformed into a giant Kun, and its heavy tail caused endless tsunamis. [1]
Sometimes it was an eagle; sometimes a Kun. The transformation became faster and faster to the point that one couldn't differentiate whether it was an eagle or a Kun. The Kun became an eagle and ascended to the heavens; stumbling on the grand truth. Kun and Peng were ever changing like the sun and the moon's rotations; it was as if they were one with the primordial orders of the heavens and earth.
"Bang!" A loud noise rang in the room, and Li Qiye initiated Kun Peng's power. In the blink of an eye, Li Qiye's whole body heavily jolted, and the gigantic Kun Peng that was thousands of miles tall suddenly disappeared. The heavy tornados and tsunamis that were accompanying the beast also subsided. These images slowly become strands of consciousness, slowly gathering into one grand truth. What emerged from this grand truth were the symbols from the erased memories that were now returning to Li Qiye's mind.
In the end, when the eagle was no longer an eagle, and the Kun was no longer a Kun, only one grand mysterious truth remained. A complete Kun Peng was formed, and the Kun Peng's Six Variants, without flaws, had appeared in Li Qiye's mind.
Li Qiye was extremely ecstatic; the heavens didn't let him down. He had finally regained his Kun Peng's Six Variants.
An unknown amount of time had passed, and Li Qiye recovered his thoughts from his deep cultivation. Although he had regained a completed merit law, and it was an extremely powerful one even among those at the same level, Li Qiye did not become complacent or arrogant. He knew his original body more than anyone else. When compared to the other geniuses, his Physique, Life Wheel, and Fate Palace were all lacking. He had to cultivate a hundred times harder to catch up to others; he had to be patient. Only then, could he obtain the Heaven's Will of this era to sweep the nine heavens and earth.
With the qualification of someone who had taught Immortal Emperors and powerful beings, he knew the principles behind the mysterious truths more than anyone else. His greatest strength and advantage was having a perfect cultivation procedure.
He started to research the Revolving Crescent Sun method. It was classified as a Life Wheel cultivation method used to train the Life Wheel and to increase lifespan and blood energy.
Every cultivator, and even mortals, all have an innate longevity gauge. Any living beings that have formed intelligence will have three things: the first was a Physique, the second was a Life Wheel, and the third was a Fate Palace.
Physique didn't need much explanation. This was the thing that contained one's life force. Without this physical base, there was no life. Even a mortal would have a mortal body. The general shape of the human race with its bones, bloods, and muscles was considered one of the best physical bases to contain life.
There was a saying regarding the Life Wheel. A tree had its growth rings, and a human has the Life Wheel. The Life Wheel was located inside the body, but it was not of physical form. It was a light that was continuously spinning. At first, without any special external tools, only the cultivator himself could see his Life Wheel. However, after successful cultivation, the Life Wheel would appear behind one's head; its shape and light would determine the strength of one's blood energy and longevity.
If a mortal lived his life without any accident, then the Life Wheel would determine his lifespan. Li Qiye's Mortal Life Wheel for example, would allow him to live to the age of sixty without any cultivation.
Physiques, Life Wheels, and Fate Palaces all have the following ranking from lowest to highest: "Mortal, Houtian, Xiantian, King, Saint, and Immortal."
All three share the same ranking system; however, under normal circumstances, cultivators couldn't change or increase their Life Wheel and Fate Palace level; these two were innately gifted to you by the heavens. As for the body, one's physique could be cultivated. For example, a person with a Xiantian's physique, through cultivation and effort, could raise it to the next rank.
Author's Note from the Daoist's classic Zhuangzi:
In the northern darkness there is a fish and his name is Kun. The Kun is so huge I don't know how many thousand li he measures. He changes and becomes a bird whose name is Peng. The back of the Peng measures I don't know how many thousand li across and, when he rises up and flies off, his wings are like clouds all over the sky. When the sea begins to move, this bird sets off for the southern darkness, which is the Lake of Heaven.
[1] Kun resembles a whale, Peng is the eagle form, I suggest googling Kun Peng if you want an image.