- “Yan’er, look at the clouds, the mountains, the sky, and the land. Remember this image. However grand your vision is, that is how grand your future can be. It is also how grand… your heart can be.
We cultivators cultivate, not the body, but the heart!„
Meng Hao [pinyin: Mèng Hào] is the main protagonist of I Shall Seal the Heavens. He was once a young scholar in Yunjie Country, who had failed the imperial exams for the third time. Sitting on Mount Daqing he was kidnapped and brought to a sect of immortal cultivators by his future beloved, Xu Qing.
Meng Hao was on his way to becoming the Immortal but due to the interference of Allheaven in the form of a war that lead to the destruction of the Mountain and Sea Realm, he choose to defile himself; starting his path to becoming the Demon.
Often said to be handsome beyond compare, with eyes that seem like stars. His looks are often described as otherworldly, a dragon among men. He is tall and once had a swarthy skin but after absorbing half the water in the Demon Immortal Cistern and forming his Eighth Anima, his skin transformed to a fair, jade-like complexion. It was white and flawless, causing him to look refined and gracious. His scholarly air became even more potent than ever, his looks even more handsome, and his aura all the more youthful and elegant. 
After becoming a Quasi-Demon
He kept his normal appearance but with black veins running throughout his entire body, and his hair grew incredibly long. His eyes turned crimson; they were like gemstones, but if you looked at them long enough, they seemed like seas of blood. His hair took on a violet color after his hair roots turned red. 
After Transcending, his violet hair became crimson and his eyes(sclera) transformed into a violet color with red pupils. Other than those, he looked pretty much the same to the way he was before he transformed into a quasi-demon. Though he's always been young-looking, all traces of age disappeared from his body.
Intelligent and stubborn. Having been a scholar in his mortal days, he is backed by knowledge he has accumulated over the years. Granted he failed thrice in the imperial exams, but his wits alone put him levels above most cultivators. His quick thinking and belligerent ways constantly puts him in precarious situations which he always gets out off using those very same qualities. He knows when to back out of a fight especially when up against opponents leaps and bounds above him, but makes them pay a hundredfold after mustering enough strength to go against them. Surprisingly, his sometimes charming but brute ways make him endearing to the opposite gender. His "never say die" attitude also makes him a person worthy of respect and admiration — alongside frustration, especially from his peers — from anyone. The vicious fighting style he continually displays incur either awe or fear from anyone who witness his fights.
He has a near obsessive attitude towards Spirit Stones, and later on Immortal jades, which stems from when he was a poor scholar with nothing to his name and also from his early days in the path of cultivation when he first acquired the Copper Mirror. This trait every so often makes him a subject of contempt to those he took advantage of. When it comes to those close to him however, he often displays a generous nature one wouldn't have suspected him to be capable of, as seen when he unhesitatingly took out millions of immortal jades to create an immortal qi field for the first bloodline of the Meng Clan. 
He hates being conned and made a fool of as much as he enjoys extorting cultivators out of their treasures— or specifically, of their spirit stones. He seemingly reverts back to his scholarly self — humble, honest, innocent and almost shy — when he starts scheming ways on how to get the cultivators he meet to owe him, in the form of spirit stones. For those who sees this trait of his for the first time, are often tricked into assuming he was simply an innocent lad, but invites scorn from those who've seen it once.
He treats others as they would treat him, he is respectful to those he deems worthy of respect and is hostile to those who don't. He sees attacks to anything closely associated to him, whether in the form of insults or otherwise, as an affront to himself. The aggressors that invites his contempt often find themselves either stripped of everything or left for dead.
Meng Hao was born on Planet East Victory in the Fang Clan. He was born with a Nirvana Brand, which is a Heaven-defying daoist magic of the Fang Clan that allows Nirvanic Rebirth up to four times. To undergo Nirvanic Rebirth it requires a deep cultivation base, as well as a very pure Fang Clan bloodline, but Meng Hao on his seventh birthday underwent Nirvanic Rebirth, reverting him back into a baby to be born again, while also producing a Nirvana Fruit.
He underwent Nirvanic Rebirth twice before Shui Dongliu came to Meng Hao's parents and told them that if they guard Planet South Heaven for 100,000 years and to not interfere with Meng Hao's Karma until he reaches the Dao Seeking Stage then Meng Hao would have a chance of surviving.
Meng Hao's parents left him before his seventh birth day. He lived in Yunjie County, which laid at the foot of the mountain. He had a dream of becoming an official.
Meng Hao stood on top of the mountain after failing the exam yet again. He was pondering on what was he going to do with his life when he heard Wang Youcai shouting for help. He claimed to have been captured with other people by a flying woman. Meng Hao decided to help them but then suddenly the mysterious woman appeared. She said that she was one person short so she kidnapped him as well. 
They then flew to the outer parts of the Reliance Sect and started working as servants for Immortals. There Meng Hao got his Qi Condensation Manual which contained basic information about the sect and cultivation tips. He started living with a 12/13 year old chubby boy, son of a Lord which Meng Hao calls him "Fatty". Meng Hao would work during the day and cultivate at night. Meanwhile he befriended Fatty using fried chicken. After 4 months he finally reached the first level of Qi Condensation and was promoted to Outer Sect. He is bestowed with a house, a green robe, a spirit tablet, and a bag of holding. The spirit tablet allowed him enter the Treasure Pavilion to retrieve a magic item. He was tricked into picking a seemingly useless Copper Mirror.
The next morning was Pill Distribution Day. His Master Uncle Shangguan and two Inner Sect Disciples were in charge of handing out pills and Spirit Stones. One of the Inner Sect Disciples was Xu Qing, the woman that brought him to the Sect. Meng Hao was supposed to get a Dry Spirit Pill as a reward for recent promotion. Realizing that this treasure will only bring him trouble, he decided to gift it to Elder Sister Xu as a gratification for letting him start a new life. She accepted the pill and lent him Immortal's Cave that she used to live in.
After entering the cave he discover a Spirit Spring. When he finished absorbing energy accumulated by spirit spring Meng Hao went out to hunt some chickens. Unexpectedly the Copper Mirror exploded the butt of the chicken. After carrying out a few tests he realized that his Magical Treasure could explode the butt of any creature that had fur, even Demonic Beasts. Finished with exploration of nearby area he went back to his cave and consumed a Spirit Condensation Pill and a Demonic Core he broke through to second level of Qi Condensation. He noticed the disappearance of a Spirit Stone and a new Demonic Core, that lead him to conclusion that his Copper Mirror can duplicate items in exchange for Spirit Stones. Upon reaching second level of Qi Condensation one can learn to use Immortal Skills. Meng Hao decided to learn Flame Serpent Art. After a failure in learning the skill he started hunting for Demonic Beasts. One month passed. He learned the Flame Serpent and killed a bear-shaped demonic beast. Later it was time for his second Pill Distribution Day. After getting monthly resources Zhao Wugang tried to take Meng Hao's cave and items. He transformed using Were-demon skill into a furry monster. Noticing the transformation Meng Hao killed him using Copper Mirror. Zhao Wugang's bag of holding contained eight Spirit Stones, seven Spirit Condensing Pills and a bone fragment covered with strange symbols. With the help of Spirit Stones and Copper Mirror Meng Hao broke into the peak of the third level of Qi Condensation.
He started a Pill Cultivation Workshop Outlet in the Public Zone.
Meng Hao, upon having created the Bedevilment Pill, decides to imprint it with a new icon, square just like the gigantic cauldron he had seen in the Violet Fate Blessed Land. When he decides to anonymously auction it, it quickly becomes a sensation. Since nobody knows much about the creator, he is named Pill Cauldron, and since it's clearly the work of a Grandmaster, this identity becomes known as "Grandmaster Pill Cauldron".
After teleporting away from Immortal's Corpse, he travels through Black Lands for 2 months until he arrives in Immortal's Cave that belongs to Huang Daxian who is at 6th stage of Qi Condensation. Meng Hao spends there 3 months healing himself. The owner of the cave comes back and without realizing that his cave was overtaken by someone, he breaks into it. After one look at Meng Hao, Huang Daxian realizes that it might the biggest and last mistake in his life. Meng Hao gives him a single Medicinal Pill of low value as compensation for using his cave. Now that he reached Core Formation he awakened the Ancient Celestial Bird, Lord Fifth from Copper Mirror. The Bird says that the Immortal Sense Soil in Black Lands is filled with ashes of burnt ancient talisman that was created in order to seal the planet by an almighty member of the senior generation. Meng Hao doesn't believe him so, Lord Fifth gives him vision technique called The Celestial Technique. He remembered that the voice of Demon Sealing Jade said that he could cultivate Righteous Bestowal. Huang Daxian got into trouble and brings 4 cultivator of Foundation Establishment. Meng Hao kills 2 and force others to consume poison pills, saying that he will dispel them once they bring him enough soil and even might give them some medicinal pills. With that he starts cultivating a new technique.
- His name, 浩 (hào), means "great" or "many".
- His surname, "Meng" (孟), is pronounced as "mung".
- He got engaged twice; he ran away both times.
- Meng Hao finally paid his debt to Steward Zhou in the final chapter of the novel.
- Meng Hao's cultivation base is said to be around half a step into the 5th step at the end of the novel.