Muzan Kibutsuji is the main antagonist in the popular anime and manga series Demon Slayer. He is the progenitor demon who created the other demons through his blood and is attempting to find a way to overcome the weakness to sunlight that all demons share.
One of the unique attributes of Muzan as the first demon is that he possesses multiple hearts and brains. This allows him to survive grievous injuries that would kill other demons. However, there is some debate among fans over exactly how many additional hearts and brains Muzan has.
Does Muzan Have 7 Hearts?
In Demon Slayer episode 19 of the first season, Muzan states that he has 7 hearts. When Tanjiro uses the Dance of the Fire God to attack Muzan, he destroys one of Muzan’s hearts. Muzan then says “You destroyed one of my seven hearts.”
This line directly from Muzan himself explicitly confirms that he has 7 hearts total. Having multiple hearts grants Muzan tremendous resilience and allows him to survive decapitation and other fatal blows. As long as one heart remains intact, he can regenerate.
So based on Muzan’s own words in the anime, he does indeed possess 7 hearts. Some fans mistakenly think he has 9 hearts due to a vague line later in the battle, but the initial claim of 7 hearts from Muzan should be considered definitive proof.
Does Muzan Have 6 Brains?
The number of brains Muzan Kibutsuji has is more ambiguous than the number of hearts. In the manga and anime, he never outright states how many brains he has. However, there are some clues that point to him having a total of 6 brains.
In Chapter 137 of the Demon Slayer manga, Obanai Iguro manages to rip out one of Muzan’s brains during their battle. After analyzing the brain, Obanai concludes that it is just an ordinary brain with no special properties.
This suggests that destroying one of Muzan’s brains does not significantly weaken him. For that to make sense, Muzan would need multiple brains like he has multiple hearts. Having only one brain remaining would leave him severely impaired.
Later in the battle, Muzan himself says that Obanai was able to pull out one of his brains because he let down his guard. This implies Muzan has other brains that can take over if one is damaged.
In Chapter 178, Tamayo comments that Muzan’s body consists of 6 identical brains with linked memories and consciousness. This line provides the clearest evidence that he has a total of 6 brains.
While not as definitive as Muzan’s own statement about having 7 hearts, the narrative clues strongly point to him having 6 brains as part of his physiology as the demon progenitor.
Muzan’s Hearts and Brains Allow Rapid Regeneration
Muzan Kibutsuji’s multiple hearts and brains grant him tremendous survivability and recovery abilities. Here’s an overview of how they function:
Hearts
– Having 7 hearts means Muzan has redundancy if some hearts are damaged. As long as 1 heart remains, he can regenerate the others.
– Hearts pump blood containing his cells throughout his body to fuel regeneration of tissues and organs.
– Destroying all 7 hearts is required to kill Muzan and stop the regeneration of his body.
Brains
– 6 brains means destroying 1 or 2 has minimal impact on Muzan’s functioning.
– Brains provide coordinated control of his body and access to his memories/personality.
– Brains are spread throughout his body, not just his head, further improving survivability.
– Destruction of all 6 brains is likely required to stop regeneration.
Some key benefits provided by having 7 hearts and 6 brains:
– Withstand decapitation or removal of other body parts
– Survive near-complete destruction of individual hearts/brains
– Rapid regeneration of tissues, organs, and lost body parts
– Redundancy prevents single fatal blows
– Difficulty stopping regeneration without destroying all hearts and brains
Weaknesses
While Muzan’s multiple hearts and brains provide him with immense resilience and recovery capabilities, he does still have some weaknesses that clever demon slayers can exploit:
– He can only fully regenerate when consuming significant amounts of human flesh and blood. Without sustenance, his regeneration is much slower.
– Injuries from Nichirin blades slow his healing factor and can prevent regeneration of severed body parts.
– He is still vulnerable to sunlight due to being a demon, though he possesses some resistance. Prolonged exposure can kill him.
– Powerful blows with Nichirin blades can still destroy hearts and brains if they are targeted precisely.
– After consuming some of Tamayo’s poison, Muzan lost the immunity he had developed over centuries. This left him more vulnerable to demon slayer attacks.
– Despite his arrogance, Muzan is cautious and afraid of death. He will flee if he perceives a real threat. Leveraging his fear makes him more prone to mistakes.
So while Muzan is incredibly difficult to kill due to his multiple hearts and brains, he is not completely invincible. Demon slayers must utilize skill, strategy, teamwork, and some luck to land decisive blows before Muzan can regenerate.
Conclusion
Based on explicit statements by Muzan in the anime and informed analysis of the manga narrative, the evidence conclusively indicates that:
– Muzan Kibutsuji has a total of 7 hearts
– He likely possesses 6 brains spread throughout his body
This unusual physiology grants Muzan extraordinary resilience and regenerative capabilities. Destroying all 7 hearts and 6 brains within a very short timespan is likely the only way to kill Muzan and permanently stop his regeneration. While extremely difficult, teamwork by the demon slayers ultimately allowed them to achieve this monumental task of finally defeating the powerful progenitor demon.