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.
Every demon in the Demon Slayer respects the demon lord because of the fear he inflicts. Even Upper-Rank Three: Akaza got thrashed boasting about executing a Hashira, insignificant to Muzan as humans are frivolity in front of demons. Apart from that, Muzan doesn't hate Akaza because of his obedience.
As stated by Doma, that Muzan had tolerated and allowed Akaza's unique aversion to not eating or harming women and even only went as far as only dispatching him on special missions only, a privilege not even given to Upper Rank 1 or 2. He was one of Muzan's favorites since he was loyal and serious.
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.
Thanks to the anime's Mugen Train arc, Akaza is currently one of the (strongest but) most hated characters in Demon Slayer.
Despite losing his memories, Akaza was noted to have subconsciously retained his strong feelings for Koyuki, this is seen where Doma noted that Akaza absolutely refused to kill and eat women during his hundreds of years as a Demon, despite his obsessive desire for more strength and power.
3 Nezuko Is The Friendliest Demon In The Series
However, Nezuko is the friendliest demon anyone will ever meet. As a human, she was just as outgoing and compassionate. But as a demon, she's proven her loyalty to not only Tanjiro, but to humanity as a whole.
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.
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.
Akaza. Because of his desire to become stronger and Doma's strength allowing him to surpass himself to become Upper Two, Akaza harboured an intense hatred of Doma.
Muzan is displeased with Akaza's "accomplishment", declaring that one victory is meaningless until the entire demon slayer corps are destroyed and that Akaza failed to kill the other three Demon Slayers at the train. He punishes Akaza by making him bleed profoundly and dismisses him.
1 Muzan Regretted Killing His Doctor
He shows his most human side to fans, wherein he admits to regretting murdering his doctor. He comments that had he been patient, the doctor would have cured him, and he would never have turned into a demon.
3 Muzan Mainly Liked Daki Because Of Her Potential To Earn Money.
5 Dislikes Him: Akaza Hates Tanjiro For Reminding Him Of His Past. Akaza had long forgotten about his memories as a human because he didn't want to remember his past. Tanjiro's words brought back those memories, which enraged the demon. When Tanjiro called Akaza a coward, Akaza was furious.
Muzan retorts it was only one Hashira and declaring his desire is for all to be dead. Angered at his failure, Muzan takes control of Akaza's cells and causes him to bleed heavily.
It was clear Tamayo blamed and hated Muzan for what he did to her, which is why she once tried to kill him. This happened a few centuries ago when Tamayo was still a fairly new and weaker demon.
8) Muzan hates being called pale or dead
Muzan is the most powerful demon in the entire series, and is responsible for creating all demons. For someone who considers himself to be perfect, it is natural that he will hate being called pale or dead. This is established quite early on.
Over his long lifetime, Muzan had a number of families. This includes the one he was born into before becoming a demon. Additionally, he took 5 wives, making each one's life miserable. Repeated abuse and torture drove them to take their lives.
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.
Tsukito, Yorogi, Kuraku, and Isatsu all agree that they are loyal to Muzan. and show the utmost respect to him.
Haruka Shiraishi: Muzan's Daughter.
Shinobu Kocho's tragic backstory is one of the most heart-wrenching in Demon Slayer. She and her sister, Kanae, were orphaned at a young age after their parents were killed by a demon.
Akaza is, by far, Demon Slayer's most tragic villain. Anime-only fans only recognize him as the demon who killed off the fan favorite Flame Hashira, Rengoku. However, his backstory drove manga readers to tears.