Watching Demon Slayer (Kimetsu no Yaiba), it is fascinating to see different kinds of characters. It is good to see that not all humans have cute or lovely faces. Some of these humans face demons early in their lives, and their only option is to be strong and fight demons.
Hashiras are the elites among the Demon Slayer Corps. They are the ones who are known for their extraordinary agility, reflexes, swordsmanship, and other skills and abilities that enable them to fight off demons.
There are no specifics on how to become a Hashira other than you need to be extremely skilled. Extremely skilled to the extent that you need to be able to fend off demons and gather information simultaneously.
Joining the Corps alone is already a tedious task; preparations could take years, and getting promoted to a Hashira could also take years. Some ranks are being followed to become a Hashira unless you are a Tsuguko or a chosen successor.
Giyu was the first Hashira that was introduced in the series. Back then, he was not called a Hashira but a demon slayer. Demon slayers are revered swordsmen in Japan who can fight demons. Later in the series, in the Ubuyashiki Mansion, Tanjiro and his friends met all 9 Hashira.
Hashira has “Destroyer of Demons” engraved on their sword. They can also retire at will. That is why there are Hashira who can still mentor the next generation of demon slayers. Here is a list of Hashira and short information about them.
Gyomei Himejima

The strongest and the tallest among the Hashira. This Stone Hashira is also the leader of the Hashira. He has a strong build and good reflexes. When he was battling Kokushibo in the Infinity Castle Arc, it can be seen how fast he was.
He is even to fight one-on-one with the Upper Moon 1 and match his speed and reflexes. Gyomei had always been strong; when he was a boy, he beat the demon using only his bare hands. Two months after joining the Demon Slayer Corps, he became the Hashira.
Gyomei, despite having a huge build, is one of the kindest and soft-spoken of all the Hashira. His immense training during the Hashira training course had been seen to be fruitful as he was one of those still able to have total stamina after fighting off the Upper Moon.
Despite his legs getting cut off by Muzan, he was still part of the battle and refused to give up. He was one of the deciding factors in driving Muzan to the corner. Among the Hashira, he did not carry a sword but an ax, a Kusarigama, a scythe, and a heavy iron weight connected by a chain.
Tengen Uzui

He is one of the flashiest of all the Hashira. He has three wives, Makio, Suma, and Hinatsuru, who helped him infiltrate the Red Light District. These are the people he deeply cared for.
This Sound Hashira wants to boast and call himself a god. Despite his flamboyant character, he values the lives of the people around him, whether his wives or colleagues.
As a former shinobi, he had no regard for the lives of others, as his brother and father had taught him, but that greatly changed when he became a Hashira. Tengen Uzui was one of the most skilled combatants among the Hashira because of his upbringing as a shinobi.
He had learned a special ability from being a shinobi and still used those abilities when he became a Hashira. Some of these abilities are echolocation, stealth, and poison resistance.
He is one of the most skilled swordsmen, almost unrivaled in the Corps. His experience as a shinobi allows him to be flexible when strategizing for battle.
Kyojuro Rengoku

The Flame Hashira is known for his warm personality. He is welcoming and is always helpful to the younger member of the group. He came from a family of demon slayers, and he is the one who is currently holding the title of the Flame Hashira.
Coming from the family of Hashira, he follows a strict code of conduct instilled in him by his father, the former Flame Hashira. This strict environment resulted in his swordsmanship and work ethic.
Even during his last moments, he still cared so much for his family that his last words were even for his brother and father. When he battled Akaza during the Mugen Train Arc, he was acknowledged by Akaza for his swordsmanship and offered to turn him into a demon.
He has an immense perception as he can sense the strength of a demonic aura. He has immense strength, and he is capable of lifting the train. He does not use any flashy weapon. He displays his fighting skills using a katana, and he is able to master all the forms of the Fire Breathing style.
Giyu Tomioka

The Water Hashira is extremely quiet. He is a man of few words. A former Water Hashira mentored him. He has a cold personality and always follows the code of the Corps, which is zero tolerance for demons.
He violated this code only when he showed mercy to Nezuko and allowed her to live. Giyu is caring towards the people he is closest to. He cares too much for those he considers his friends.
He is also a good teammate and does not mind mentoring the new generation of demon slayers. As a Hashira, it is expected of Giyu to be a highly skilled combatant. He has great reflexes and stamina.
A former Water Hashira mentored him, and he was able to master all the forms of Breath of Water. He is very strict with his training regimen. As a result, he has immense reflexes, stamina, and endurance.
Shinobu Kocho

Behind the cheery and carefree attitude lies a deadly Hashira. She is the Insect Hashira and is known to develop different kinds of poison and medicine. She came from one of the most affluent families and owned the Butterfly Manor.
Her hatred for demons knows no equal. She had lost all the people she loved and those she cared for to demons. Shinobu always wears a smile; even when she is already killing a demon, she still smiles before the execution.
Shinobu is known to have a keen intellect and medical expertise. She could easily calculate the situation based on the little information she has. She also likes gathering information. Her medical expertise allows her to develop the poison that will defeat Muzan.
This poison she develops with Tamayo, who has a vast knowledge of demons and demon transformation. She also altered her body so that every cell would contain poison so that when she battles with Doma, she can stop him from regenerating.
Mitsuri Kanroji

The Hashira of Love is one of the strongest female characters for a reason. Her body is eight times denser than any regular human’s. She joined the Corps not to fend off demons but to find a suitable husband.
She can get very excited and always shows how much she cares for others. She likes to hug her friends and always expresses her feelings for them. She is extremely dedicated to the cause of the Demon Slayer Corps.
While she is always kind and caring to her friends, this is the opposite regarding the demons. Aside from having very dense muscle, She had mastered all the forms of the Love Breathing style.
As a Hashira, she is a highly skilled combatant, and this was seen during the Swordsmith Village Arc, where she was able to defeat the clone form of the Upper Moon 4. She had a cat when she was a child. so even if she uses the Love Breathing style, the forms are mostly named after a cat.
Sanemi Shinazugawa

The Wind Hashira is hot-blooded, impulsive, and extroverted. His brother Genya joined the Corps to look for him, but he would hurl insults at him instead of welcoming him to the Corps.
Tanjiro said that despite the outward appearance of Sanemi, he greatly cared for his brother. He wished for him to settle down, have a family and stop being a demon slayer so he could be out of harm. Losing his family to demons, he believes that all demons are vile.
This was displayed when Nezuko arrived at the Ubuyashiki mansion. He lost his brother in his battle against Kukoshibo but had to recover from it quickly. He assisted other Hashira in their fight against the Demon King, Muzan.
When Sanemi was fighting the Upper Moon 1, he was complimented by Kukoshibo, saying that his physical prowess had reached his peak and he was in another league, even among his fellow Hashira.
Obanai Iguro

Being surrounded by women and getting abused by them, this Serpent Hashira developed a fear of women. He hates people who do not abide by the code of the Corps.
He got extremely jealous of Tanjiro, who always sat with Mitsuri during meals. Obanai love showering the people he loves with gifts. This was proven true with Mitsuri, who he cared for deeply. While the cars for Mitsuri are too much, the same is not true for others as he is merciless even with his fellow Hashira.
This Hashira is one of the strongest, considering that he rises to the ranks of the Hashira with only one functioning eye. In the final battle against Muzan, he took a hit for Tanjiro, and when he was about to be eaten by Muzan, he landed a blow on him to weaken him more.
Obanai was one of the Hashira who lost their lives to bring down Muzan. His death had greatly saddened Mitsuri, and she wished they would be reincarnated and together in their next life.
Muichiro Tokito
The Mist Hashira has a twin brother, Yuichiro Tokito, who died fighting a demon. They lost their parents at such a young age, and while Akame Ubuyashiki had been recruiting them, they would have to decline continuously.
It was only when his brother died that he finally decided to join the ranks of demon slayers. Muichiro did not care much about his surroundings. He is a capable Hashira, but he does not care for anybody around him.
Muichiro is a child prodigy who accomplished his Hashira Status only two months after training. He can easily defeat the other demon slayers that are older than him. In Swordsmith Village Arc, he could quickly subdue Gyokko, the Upper Moon 5, even in his real form. He died, sacrificing his life to defeat Kukoshibo.