The Mist Hashira, along with Gyomei, Sanemi, and Genya, fought the Upper Moon 1. While the group was able to defeat them, both Muichiro and Genya died due to the wounds inflicted by Kokushibo.
After the fight, he tries to find Mitsuri, and both confess the love they had for each other. Obanai held Mitsuri in his arms, and the two succumbed to their injuries. These were all the Hashira who died in the series. The only Hashira who have survived are Tegen, Sanemi, and Giyu.
2) Rengoku
However, Rengoku was forced to face off against Akaza who was Upper Moon 3. The Flame Hashira carried out his duties until his death as he did not let his comrades get injured. Akaza managed to put his fist through Rengoku's solar plexus which mortally wounded the Hashira.
Shinobu Kocho is a capable Demon Slayer whose worthy of being the Insect Hashira. That being said, she's arguably the weakest Hashira when it comes to pure strength. However, brawn is not the only way to determine power in Demon Slayer.
We first see Doma when he is still the Upper Moon Six while he is in the middle of eating a geisha. Later he becomes even stronger and rises to the position of Upper Moon Two. He dies because of the lethal amount of poison he absorbed through Shinobu Kocho's body followed by Kanao Tsuyuri beheading him.
Gyomei Himejima, the Stone Hashira, is the strongest Hashira in the Demon Slayer corps in terms of strength and swordsmanship. He is the only person who uses spiked flails and an axe instead of standard swords to kill demons.
1 Gyomei Himejima - The Stone Hashira
The oldest of the bunch, the Stone Hashira, Gyomei Himejima is 27 years old.
At some point, Daki fought, killed and ate seven Hashira.
The Wind Hashira has one of the saddest backstories in Demon Slayer. His mother had turned into a demon and had killed five of his siblings. He was forced to kill his own mother in an attempt to save his only remaining brother, Genya.
No one killed Sanemi Shinazugawa. Sanemi almost died when he tackled his sister Genya from a window in order to protect her from a demon attack, but was saved by his friend Masachika who healed his wounds.
However, Giyu Tomioka does not marry anyone in Demon Slayer manga. While romantic subplots do exist in the series, Giyu's character arc focuses primarily on his growth as a warrior and his relationships with fellow demon slayers.
Rengoku. Of Demon Slayer's saddest deaths, Kyojuro Rengoku's hurt the most. Those who watched Demon Slayer – Mugen Train, witnessed the despair Tanjiro felt when he saw Rengoku fight Akaza, the Superior Moon Three. The manga brings this death with sadness, but the moment becomes much more exciting in the anime.
Giyu is one of the first Hashira introduced in Demon Slayer. He plays a vital role in Tanjiro's development and is the main reason Nezuko is allowed to stay with him.
Muichiro Tokito: The Mist Hashira with a Mysterious Aura
Despite being blind, he maximizes his concentration through painful memories, making him a formidable fighter. His toughness, concentration, and immense strength make him an unbeatable force, and he is widely regarded as the strongest Demon Slayer in the Corps.
But there is one who is the friendliest of them all, and that is Kiyogiro Rangoku, the Flame Hashira. Among the pillars, there is not a single negative thing revolving Rangoku. Such an honest guy, and his character influences others positively. In Demon Slayer, Liu and Rangoku are not shown to have any interactions.
1) Tengen Uzui
Without a doubt, the flamboyant Tengen Uzui is physically the fastest Hashira in the Demon Slayer Corps.
Since she's the Love Hashira, it just makes sense for Mitsuri to be one of Demon Slayer's kindest and most compassionate characters. She always compliments the people around her, even if it's just mentally. She can also find everybody's best qualities.
But the crowning moment of his achievements is when he epically slices off Daki's head and makes a run for it—after all, she won't die until her brother's head is also sliced. Unfortunately, Gyutaro spots Inosuke and stabs him right through where his heart should be with a sickle imbued with deadly poison.
How Doma became the worst demon in Demon Slayer. Almost every creature possesses emotions, be it anguish, sorrow, happiness, or even fear. However, in the case of Doma, he doesn't feel a thing. During his childhood, his mother stabbed his father to death for cheating on her and, later on, took her own life.
Tomioka Giyu = killed by Tanjiro Kamado. Tanjiro Kamado = killed by Nezuko kamado ( or another demon ) ; or executed for killing a hashira and have protected a demon. Nezuko Kamado = burned to sunlight , killed by a hashira , or eaten by Muzan Kibutsuji ( if she conquires the sun )