Curse of Kibutsuji This curse besotted any who partake of Muzan's blood must be careful. The curse prevents Muzan's name from being spoken aloud, and any who do will meet a horrible demise. One demon, Susamaru, faced this reality when battling Tamayo.
Demon Curse: Muzan places a curse on all demons that have assimilated his blood. If any demon divulges his last name "Kibutsuji" out loud, the curse activates, which causes their bodies to stop regenerating and allowing Muzan's cells inside the demon to take over and kill them, regardless of their original intent.
Muzan's own blood is also shown to have special properties that can strengthen a demon, proportional to the amount of blood infused.
Drinking a vial of Muzan Blood as a hybrid will cause many problems to arise; you lose your Breathing Style, and will become incapable of learning new (or old) styles. If you have a unique Nichirin Sword, you would still be able to retain ownership of it.
However, she wasn't immune to the sunlight initially, as she got burned badly at first. So, in conclusion, her coming from a Sun Breathing user's lineage and not relying on human substance are perhaps the reasons for her immunity.
The only thing he's weak to is the sun. That is why he turned other humans into demons and spread his blood so that one of them might find a solution against the sunlight, so he can become truly perfect.
Even 400 years later, Muzan's fear of Yoriichi remained fully intact, as simply laying eyes on Tanjiro's hanafuda earrings caused him to recall their clash.
Abilities. Demon Body: Unique from other demons, he possesses seven hearts, and five brains. These are responsible for his powerful vitality, should any of them be harmed, he will be severely weakened.
After he neutralizes Tamayo's poison and emerges from his flesh cocoon, Muzan's hair grows in length and turns white due to Shinobu's poison accelerating his age.
When Demon Slayer's Tanjiro met Muzan in Tokyo, Muzan had a human wife and daughter with him. There's a chance he genuinely cared for them. In the story of Demon Slayer, demons are supernatural creatures of the night who consume human flesh to survive. They are weak to sunlight, making them a variation of vampires.
Akaza was also one of Muzan's favorite demons out of all his subordinates. The reason behind this is Akaza's extreme loyalty to his master. The Upper Rank Three demon was always sent away on special missions, something the Upper Rank 1 and 2 were often denied of.
Yoriichi was incredibly proficient in his Sun Breathing, being able to take down demons effortlessly and even overwhelm the Demon King and strongest Upper Rank.
Muzan's ultimate goal is to attain an immortal body. He wanted to be able to walk in the sunlight and live forever. In order to gain this, he needed two things: the Blue Spider Lily and the body of a demon who could withstand the sun.
Events. It is revealed that Tamayo's drug had an aging potion mixed in along with the Demon antidote. Due to this, Muzan has aged 9,000 years within the span of three hours.
For those who have watched only the first season of the anime, they will be surprised to know that Muzan turns into a woman in the second season. He keeps transforming in order to hide his true identity, and he's even known to change into an 11-year-old child to hide from Demon slayers.
Being a demon, Muzan is capable of living for many, many years. However, unlike other demons that have aged over hundreds of years. Muzan is well over 1000 years old. Despite achieving an age that no one else has, his appearance makes him look like an adult man in his early to mid-30s.
The explosion, which was enhanced by spike traps, manages to injure Muzan. Before he is able to regenerate fully, Tamayo appears and uses her Blood Demon Art to keep him in place, while using a drug that can turn him into human. Using this opportunity, Gyomei Himejima appears and destroys Muzan's head.
Technically, the elder of the two Sakuras` was actually Muzan`s child, by way of his mistress (Lady Jade Wong), who had one of her eggs inserted into Anne`s body.
Yoriichi lived until around 85 years, so: 1432 + 85 = 1517, exactly 400 years prior to when Kokushibo remembered and died.
He steadily developed his powers over centuries and eventually became Muzan's second most powerful subordinate and held the position of Upper Two of the Twelve Kizuki. Doma seemingly adored Muzan and would continually talk to him as if Muzan were his friend.
Muzan himself never thought highly of Daki and didn't reciprocate her devotion whatsoever, only ever talking to her to sweetly manipulate her into defeating Demon Slayers on his behalf.
Since he didn't know anything about the Blue Spider Lily medicine, he needed others to find the plant for him by happenstance. This is the general reason why Muzan turned Nezuko into a demon. More specifically though, was the fact that Nezuko was of Kamado blood.
It involves covering a Nichirin Sword with Nezuko Kamado's Exploding Blood to raise its temperature to the point it turns bright red.
Over a century ago, Doma held the position of Upper Rank Six ( 上 じょう 弦 げん の 陸 ろく , Jōgen no Roku?), and during that tenure, he turned Gyutaro and Daki into demons and introduced them into the Twelve Kizuki.