He is over a thousand years old and has gained almost immortality.
Though Muzan is over 1000 years old, he looks to be in his late twenties.
Being a demon, he has gained immortality, but it has one weakness, Muzan Kibutsuji cannot go into the Sun.
Like all demons, Muzan cannot bear sunlight. As soon as he is exposed to sunlight, the Demon’s skin starts to burn, and the cells start to disintegrate.
Muzan Kibutsuji can transform humans into demons by giving his blood into their bodies.
The more blood a human receives, the stronger demon he becomes.
But it also depends on the receiver’s ability to accept the demon king’s blood.
If he receives huge quantities of it, he might not be able to withstand its effects, and its body would disintegrate and explode.
Muzan is on his quest to attain complete immortality and become the supreme being.
He desires to conquer the Sun and be able to rule the world.
To become unaffected by sunlight and overcome his only weakness, he seeks a solution, the Blue Spider Lily, a rare flower that might cure him.
For over a thousand years, Muzan had been searching for this cure and creating more demons to ultimately create a demon that could conquer the Sun and fulfil his dream.
Even though he is searching for this, how do you think he became a demon? He was the first demon to come into existence.
And why cannot he withstand sunlight? Let’s look into it in detail and find the answer to the most important question in Demon Slayer.
How did Muzan Kibutsuji become a Demon?
Kibutsuji Muzan was born just like an ordinary human child, but he was very weak and fragile.
The doctors said that he would not even live up to his twenties.
He was very sick, and no medicine or cure worked for him.
Then his doctor suggested him a prototype medicine.
It was untested, but there was a possibility that it could cure him.
So, Muzan decided to try it out.
The medicine was made from the Blue Spider Lily, a rare flower whose location was unknown to Muzan.
After taking medicine, his condition did not improve at all, or at least that’s what Muzan believed.
The treatment was still undergoing and had not been completed, but Muzan was furious and killed his doctor.
It was later that he realised that Medicine was taking effect slowly, and he would gain immortality.
But, he couldn’t withstand sunlight and therefore could not go out during the day.
He also realised that he craved human flesh, and only that could satisfy his hunger.
After performing his first crime by killing his doctor, he left humanity and thus devoured humans as he pleased.
His treatment was incomplete, and that prevented him from going into the Sun.
But, the effects of the medicine were beyond anything seen.
His strength and physical abilities increased many folds, and he gained various abilities like the power to regenerate lost body parts and blood demon arts, thus, came the First Demon in Demon Slayer.
Muzan also discovered that if his blood were injected into any human’s body through wounds or other means, they would also become demons like him, though weaker than him.
What was Muzan’s Goal and Objective in Demon Slayer?
Muzan had only one Goal and Objective in his life.
It was to become the ultimate perfect being.
He was much more powerful than any human could ever become, but he had one weakness.
He could not withstand the Sunlight.
So, he used two ways to achieve his goal.
Firstly, he searched for the rare Blue Spider Lily so that he could complete his treatment and cure himself completely to be able to go into the Sun.
He is also using his blood to turn more humans into demons in the hope of creating a demon who can conquer the Sun.
Then he can finally become immortal by absorbing the demon.
This way, he can become the supreme being and achieve his goal.
Who is Muzan Kibutsuji Scared of?
The Demon King Muzan Kibutsuji had lived for over 1000 years and killed millions of innocent humans or turned them into demons.
On his orders, his demons and the Upper Demon Moons have killed hundreds of demon slayers, including many Hashiras.
But, there was one member of the Demon Slayer Corps who almost killed Kibutsuji Muzan and brought the demon king to the brink of death.
Muzan had to flee from his fight and barely managed to survive and save his dear life.
Muzan thus fears the demon slayer who almost brought him down.
The demon slayer is none other than Yoriichi Tsugukini, the creator and first user of the Sun Breathing Technique.
He created all the breathing styles that exist.
Yoriichi used his Sun Breathing and defeated Muzan.
So, Muzan fears the Sun Breathing Technique and even his cells that have been inserted into the Upper Demon Moons recognize the fear and Upper Demon Moons shiver with fear.
During the fight with Tanjiro, Upper Demon Moon Six Daki experienced it, and her body feared him even though she herself had never seen it.
Yoriichi wore a pair of Hanafuda earrings which were given to him by his mother.
After his death, he asked them to be passed down into Tanjiro’s family along with the original Sun Breathing Technique.
The Hanafuda earrings are a symbol of the Sun Breathing user, and thus Muzan fears it.
When Muzan encountered Tanjiro, he ordered many demons, including the Upper and Lower Demon Moons, to assassinate him.
The Demon King fears death, and the only person who can kill him is a Sun Breathing user.
Why did Muzan Kibutsuji kill Tanjiro’s family?
The real reason why Muzan Kibutsuji killed Tanjiro‘s family has not been revealed in anime yet, but there is a theory that suits them best.
Since the Kamado family is not related to Yoriichi by blood, Muzan might not have known about them before.
He might have got some idea about the bearers of Hanafuda earrings and came himself to eliminate them as they reminded him of his defeat.
In the past, after Yoriichi’s death, Muzan Kibutsuji and the Upper Demon Moon One, Kokushibokilled every disciple of Muzan and all those who knew anything about the Sun Breathing Technique because he feared that it was the only Technique that could kill him.
So killing Tanjiro’s Family (bearers of the Hanafuda earrings) might be his way of taking revenge for his defeat to Yoriicichi Tsugikuni.
But unfortunately, this would eventually lead to his demise as Tanjiro, the last and final user of the Sun Breathing, will kill him.
Why does Muzan Kibutsuji hate Tanjiro Kamado?
Muzan hates Tanjirofor being the successor of Yoriichi Tsugukini, the creator of Sun Breathing, who defeated Muzan.
Tanjirowears the Hanafuda earrings passed down in his family, which originally belonged to Yoriichi.
The earrings remind Muzan of his defeat and humiliation.
Muzan hates Tanjiro as he believes that he will be the next Sun Breathing user and thus orders the Upper Demon Moons and many other demons to kill him.
Who is stronger than Muzan Kibutsuji?
Muzan Kibutsuji is the strongest demon.
During the final battle, he was able to single-handedly fight five Hashiras and Tanjiro, Inosuke, Zenitsu, and Kanao.
Muzan is resistant to all kinds of poison and gains immunity against any poison in a short time.
He also has instant regeneration, which can only be stopped for a few moments by Sun Breathing which eventually burns the cells.
The only person stronger than the demon king Muzan Kibutsuji is Yoriichi Tsugikuni.
His breathing technique and the demon slayer mark made him the strongest.
But, no other demon or demon slayer can alone match up to Muzan Kibutsuji.
So, what do you think about the demon king Muzan Kibutsuji? Isn’t he one of the best antagonists with interesting background stories?
Let us know what you think about Demon Slayer and the Demon Moons, Hashiras and Demon Slayers in the comments below.