Don't go! DON'T LEAVE ME HERE! Muzan speaks his final words as he loses control over Tanjiro.
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. Susamaru accidentally shot Muzan's name aloud, attempting to defend his honor with her mind clouded.
It is revealed that Muzan's true fear of dying and immense desire to live and survive was due to him being born "dead," where his heart would constantly stop in his mother's womb and was assumed stillborn until he fought to breathe before his cremation.
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. As he slowly disintegrates, Muzan tells Tanjiro to make his dream come true and destroy the Demon Slayer Corps in his place.
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.
Upper-Rank One: Kokushibo
Muichiro, Genya, Sanemi Shinazugawa and Gyomei Himejima fought together against Kokushibo, though Muichiro and Genya were no match for him and were killed. Sanemi and Gyomei decapitated Kokushibo, but he successfully regenerated his head just as Akaza had.
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. Muzan is the powerful King of all the Demons, who has the ability to inject his victims with blood that allows him to convert them into more Demons.
Yoriichi defeated Muzan in an instant, but he had a question for him before eliminating him, which allowed Muzan to escape.
Between all of Tanjiro's skills and his mannerisms, Muzan is certainly scared of Tanjiro. Tanjiro represents and certainly ends up being the core threat to Muzan's quest to step back into the sunlight.
The manga explains that Muzan found Tamayo four centuries ago when she was begging him to cure her of her illness. He turned her into a demon without telling her, and she went crazy. She mercilessly massacred her own family and after she was done, she cried for her loss.
Since Muzan favored Gyutaro so much, he chose to incorporate the latter's sister Daki as well. The demon king believed that she was the only tool that could be used to control Gyutaro.
Muzan likely believed it possible that one day, Doma could become strong enough to survive sunlight, so killing him might've been detrimental to the reason Muzan made him a demon in the first place.
Moreover, while she was asleep, Urokodaki performed a unique hypnotism on Nezuko, making her believe that all humans are her family and she must not hurt them in any way. With her immense fondness for humanity, Nezuko broke out of Muzan's control, becoming free to do anything at her will.
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.
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.
Muzan is shown to have a positive master-servant relationship with Daki, as the young Demoness seemingly worships and admires the Demon Progenitor immensely, fervently hanging on each and every one one of his words and doing her absolute best to accomplish the tasks he gives her.
Yoriichi Tsugikuni, the first swordsmen to ever use Breathing Styles, once nearly killed Muzan with Sun-Breathing, and Muzan has been both physically and psychologically scarred ever since.
Thus, Muzan created demons for hundreds of years even when he didn't want to turn someone. 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.
Shinobu Kocho was the former insect Hashira who played a big role in defeating Doma, the Upper Moon 2, during the Infinity Castle arc. He also happens to be a descendant. Reason of death: Killed by Doma (Upper Moon 2).
It became clear when he defeated the Upper 5, Gyokko, single handedly. Even after taking huge damage from poison, Tokito overpowers Gyokko with his signature Mist Breathing.
Realizing the danger to himself, Muzan remotely detonated Nakime's head through his influence, killing Nakime, although her body still remained active for sufficiently long time to bring the fortress into the surface. This attempt at self preservation effectively eradicated the Twelve Kizuki.
Haruka Shiraishi: Muzan's Daughter.
Some of the characters who have faced Yoriichi and survived
This happened due to a treatment that had gone wrong. While he was being treated, Muzan killed the doctor because he was not able to observe any results.
Conversation. Fun fact: The reason why Enmu was able to say Muzan's name out loud without dying is because they're married!