The only reason why Muzan hates Doma is because of his insincerity and lack of emotions. This might sound odd, expecting emotions from a demon, but even a demon has to retain such tendencies to keep things in order.
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. Doma, as apathetic as he is, considered him his "best friend", seemingly ignoring the contempt Akaza possessed.
Doma is the misanthropic cult leader of a Eternal Paradise Cult and is responsible for the deaths of Inosuke Hashibira's mother, Kotoha, and Kanae Kocho, the elder sister of Shinobu Kocho (who Doma also kills), and the adoptive older sister of Kanao Tsuyuri.
Akaza clearly hates his fellow Demon comrades, especially Doma. And this hate isn't random, as there's a deep psychological reason behind it. The hype around the first episode of Demon Slayer season 3, the Swordsmith Village Arc, was real, and fans were not disappointed.
Akaza hates Doma because Doma became the Upper Rank 2 even though he joined the Twelve Kizuki much later than Akaza. Akaza was simply envious of him, just as he was envious of Kokushibo, which is the source of his hatred, although he was very much aware that Doma was significantly stronger than him.
Doma's false tears over Akaza's death. After Akaza's death, Doma says that he felt as if the Upper Rank had turned into a different creature before he died, and that his demise is inevitable because he never ate any women.
Doma is always smiling and acts very friendly, but this cheerful, caring nature is simply a facade. He states that he cares for his fellow Upper Moons and even cries when he learns that Akaza died, though, in fact, he doesn't feel anything for them. Even when he was human, Doma didn't feel any type of human emotion.
However, after his death, he accepted that he is wrong and that Heaven and Hell actually do exist. Doma also displayed what arguably is his first true emotion, love, when he proclaimed his love for Shinobu after finding her cute.
Inosuke's Father Was Abusive
Doma tells Inosuke that his mother was singing a lot, particularly a lullaby called “pinky promise.” It seemed as if mother and child were safe and happy at last; however, when Kotoha soon found out that Doma was a Demon and eating some of the worshippers, their happiness crashed.
Does Muzan have a favorite demon? Despite the fact that Muzan. is always shown to have disdain for his creations, Muzan does in fact have a favorite. On that list is Naki, made due to a convenient blood demon.
In a nutshell, Muzan, being the progenitor of demons, is not scared of Doma. However, he is irritated by his inability to decipher Doma's thoughts and feelings, which is the ultimate control he has over all of his creations. Upper-Rank Two: Doma is a nihilistic maniac and a misanthropic cold-blooded demon.
Her background as a courtesan coupled with her beauty meant that she would serve as a great and reliable source of income for Muzan, which is why the Demon King decided to be tolerant of her apparent stupidity.
Yet an official Demon Slayer "fanbook," written by the manga's creator, Koyoharu Gotouge, revealed Muzan doesn't really like Upper Rank Two demon, Doma. As Lower Ranks Six, Four, Three and Two can attest, Muzan is not averse to eliminating demons he doesn't care for, even if they're Kizuki.
Douma said that he had never felt emotions before, but his heart felt like it was beating now. He started doubting his belief that heaven and hell didn't exist and started blushing at Shinobu, quickly developing a crush on her. He told her that she was cute and asked if she wanted to go to hell with him.
Shinobu holds a strong resentment and hatred for Doma, due to him killing her older sister, Kanae. This hatred and disgust becomes even stronger when she actually meets him and comes to understand and see first-hand his twisted personality and ideas about giving his disciples "salvation" by killing and eating them.
It was later revealed that Akaza's desperate and stubborn pursuit of strength was to heal his sick father and to protect the ones he loved and cared about, namely his fiancée Koyuki and his teacher Keizo.
In her final moments, she apologized to Inosuke for failing to protect him and tosses him into the river as an attempt to save his life. She was ultimately killed and eaten by Doma, who claimed to have devoured her to the bone.
He died while fighting Shinobu and Kanao, with the former having dosed herself with enough Wisteria poison to kill Doma; as Doma ingested her, the poison started working, and Doma was soon killed. Shinobu sacrificed herself to kill the powerful Demon.
After the final battle
At the end of the chapter, there is a picture of Inosuke giving acorns to Aoi while she smiles. It is confirmed in the Volume 23 extras that Inosuke and Aoi did eventually end up together and that they have two great-grandsons, one of which is Aoba.
The only two people she really cares for are Muzan Kibutsuji and her older brother. She shows deep respect for Muzan Kibutsuji immediately falling into a bow when he appears. Although she cares and loves her brother she is seen insulting and blaming him at times when things aren't going well.
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. However, he deemed Daki weak and believed she was the prime reason for her brother's death.
The warrior Muzan feared was a swordsman named Yoriichi Tsugikuni. Yoriichi was the only slayer before Tanjiro who came close to killing Muzan, and the flashback of their fight occurred in Chapter 187.
4) Doma - 133 years
His demon abilities were quite troublesome as it manifested in the form of ice. Shinobu had to sacrifice her life in order to make him weak enough for him to be killed by Inosuke Hashibira and Kanao. He had lived for over 130 years and killed many humans and members of the Demon Slayer Corps.
doma has a crush on shinobu.
Is this because Akaza was formerly the Upper Moon 2 and Doma stole his position by requesting a blood battle with him? Because Akaza has lived longer than Doma.