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.
The Blue Spider Lily medicine was also the cause behind Muzan's demonification, granting him a strong body and possibly changing his blood to have transformative properties, enabling Muzan to create more of his kind as well as hold dominion over them.
The first demon that is said to have existed was Muzan Kibutsuji. The one who turned him into a demon was a generous doctor from the Heian Period, who wanted to save Muzan from death since, at the time, he was diagnosed with a disease which would kill him before he turned twenty.
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.
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.
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.
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.
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.
Muzan Kibutsuji (鬼舞辻無慘, Kibutsuji Muzan) is the main antagonist of the Demon Slayer: Kimetsu no Yaiba fantasy action manga and anime series. He is the powerful King of the Demons.
Muzan is a tall and muscular man, with an unnaturally pale skin complexion that can be easily confused as being unhealthy and sickly.
Later it is revealed that he married fellow slayer Kanao Tsuyuri, In the Modern World, Tanjiro and Kano had Great-great-great grandsons named: Sumihiko Kamado and Kanata Kamado.
What is the disease of Muzan? Muzan was born in Japan's Heian era, to a constant struggle to survive on account of his frailty. His heart stopped multiple times in his mother's womb, and when he first entered the world, he was deemed stillborn, having no pulse and not breathing.
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.
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.
Muzan Blood is also used for becoming a Hybrid if you are currently a Demon Slayer, you must talk to Kokushibou in the snow biome as a Demon Slayer when you are level 50 then you must drink 5 Muzan Bloods to become a Hybrid. But you will lose half of your levels as the cost of becoming a hybrid.
As he gives all of his blood to Tanjiro, Muzan says that if the boy survived this he would become the strongest Demon ever. Since he was the brother of Nezuko Kamado who was the first Demon to develop an immunity to sunlight and also the only one capable of using the Breath Style of Yoriichi Tsugikuni.
The only downsides to becoming a hybrid is the loss of Red Nichirin, however, the Red Nichirin buffs still remain as a passive, You will not be able to stand in the sunlight unless you are a Kamado, And you will lose access to Sun Breathing.
There is no logical reason in relation to the plot that suggests why she has a horn. While fans might assume the horn grows on people with some relation to the sun, this wasn't the case for Tanjiro, who also turned into a demon. The only other reason that could explain the horn's existence is purely aesthetic.
However, the trait that sets her apart from all other demons is the fact that she has the ability to conquer the sun, prompting the Demon King to call her the "chosen demon". Abnormal Demon Physiology: As the "chosen demon", Nezuko has several unique demonic traits that set her apart from all other demons.
Nezuko is at least stronger than Daki, meaning that if Muzan could bring her back under his control, she would certainly qualify for the most prestigious title a demon can hold: a member of the Twelve Kizuki. Thanks to Nezuko's remarkable strength, she would have to be an Upper-Moon.
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.
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.
Eventually Zenitsu and Nezuko would marry and start a family as evidenced by their descendants.
Zenitsu Agatsuma
She apparently views Zenitsu as a "weird dandelion" and did not initially seem to reciprocate his feelings. Although the two are rarely seen interacting together, Zenitsu treats her with affection and care.