1) Muzan - over 1000 years However, he failed since the
Kokushibo was a human during the Sengoku era, and was the older brother of Yoriichi Tsugikuni.
Despite her animosity for him, however, Doma would slowly develop an admiration for Shinobu as she struggles fighting despite her small stature and inability to poison him fatally.
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.
Only two Slayers were ever known to be older than 25 with a Mark. Yoriichi lived till old age, likely due to him having been born with the mark and thereby avoiding the curse altogether. Gyomei on the other hand did not activate his Mark until he was already older than 25.
Demon Slayer's season 3's latest episode has left fans on edge with Tanjiro's discovery of Yoriichi Tsugikuni's Type Zero sword.
Tanjiro's connection to Yoriichi is not through blood relation, but through their similar appearances, which is due to the divine nature of Sun Breathing.
Red Light District Arc. Doma was first seen in the main story during the Upper Moon meeting in the Dimensional Infinite Fortress, after the deaths of Daki and Gyutaro, the duo of Upper Moon Six.
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.
Fortunately, Zenitsu was able to single handedly beat the Upper Moon 6. Not only did he defeat the demon, he also created a seventh form called the Flaming Thunder God. These are the demons who have been given the title of Upper Moon 6 in Demon Slayer.
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.
Ever since he was in his mother's womb, Muzan was extremely frail and weak. The menace of death constantly haunted him: his heart stopped more than a few times when he was a developing fetus, and he was declared a stillborn upon birth due to having no pulse or breath.
12 Tengen Uzui
The Sound Hashira is the second oldest out of the main Demon Slayer cast. Tengen's uniqueness shows in both his appearance and personality, but he can still hold his own as a Hashira.
Yoriichi Tsugikuni is a Demon Slayer from 300 years ago, and the inspiration for Kotetsu's training doll.
He was a genius when it came to swordsmanship and nearly killed Kibutsuji Muzan all by himself. So now, Tanjiro, the protagonist of the Demon Slayer series, has access to a sword that belonged to the best swordsman to have ever lived.
This is the sword that appeared out of the neck of the doll at the end of Demon Slayer season three's second episode. In the manga Tanjiro has the sword repaired by Haganezuka, who he initially traveled to the Swordsmith Village to find.
2) Kokushibo
This Upper Moon 1 went up against Yoriichi and managed to make it out alive. He gave everything he had but still managed to receive a heavy slash. Just before he received the second cut, Yoriichi died when he attempted to recover from the first move.
When Yoriichi moved forward to kill him, Muzan used the remains of whatever power he had left and divided his body in a powerful burst. Though Yoriichi was able to destroy nearly all the fragments, the pieces he missed escaped and allowed Muzan to regenerate again.
Demon Slayer Mark: Yoriichi is the progenitor of the Demon Slayer Mark, being born with it, possessing the tremendous physical abilities granted by its effects all throughout his lifespan.
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.
He considered these stories extremely boring and was confused why they came to a child for help. These people asked him to lead them to paradise, causing Doma to cry, since he never believed paradise, the gods and Buddha were real.
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.