KRD.

Kanao Tsuyuri has thin black hair pulled back into a ponytail on the right side of her head. The ponytail is secured with a pink and green butterfly-shaped pin—this pin originally belonged to her adoptive sister, Kanae Kocho. She calls Shinobu (her adoptive sister) "Mentor." She always makes decisions with a coin. She's quiet.

Tanjiro Kamado is a kind and good person. After his sister became a demon, he joined the Slayers to turn her back. He has a red-burgundy scar on his forehead. He masters the Breath of Water and the Fire God Dance.
Zenitsu Agatsuma is a cowardly fellow. When he falls asleep, he can fight very well, but when he wakes up, he won't remember it. He masters the Breath of Thunder. He only knows the first style: "Lightning Thunderclap."
Inosuke Hashibira is a brave and slightly crazy guy. He doesn't like to think too long. He almost always goes for broke. He wears a koban head on his head as a mask. He masters the beast's breath. He fights with two blades at once.
Nezuko Kamado is Tanjiro's sister. She was transformed into a demon, but retained her human intelligence and protected people. After the battle with Hantengu, which also involved Tanjiro, Inosuke, Zenitsu, and Mitsuri, she reverted to human form, but not completely. Her eyes remained demonic, she retained her fangs, and she lost the ability to speak humanly.

Tamayo is a demon and former doctor. Muzan transformed her into a demon during the Sengoku era, after which she killed and devoured her family. Over time, Tamayo freed herself from Muzan's influence, retained her humanity, and devoted herself to studying demons and finding a way to reverse the transformation, but to no avail.

Yushiro is a demon whom Tamayo transformed into a demon when he was terminally ill. He became her faithful assistant and protector. He is skilled in medicine.

Giyu Tomioka - The Water Pillar.
Mitsuri Kanroji - Pillar of Love.
Muichiro Tokito - Pillar of Mist.
Gyomei Himejima - Pillar of Stone.
Obanai Iguro - The Serpent Pillar.
Sanemi Shinazugawa - Wind Pillar.
Shinobu Kocho - Insect Pillar.

Muzan Kibutsuji is the main antagonist. He is considered the first demon in the world. However, this powerful demon had a weakness: sunlight became fatal to him, as it is to other demons.

Akaza - holds the position of Upper Moon 3. Hates Douma.

Douma is the Second Upper Moon. He has no emotions and therefore always smiles and rejoices at the deaths of others (he usually kills girls).

Kokushibo holds the position of Upper Moon One. He is very serious. He fights with a katana and moonbreath.

Kaigaku holds the position of Upper Moon Six. He loves to joke and kill. He fights with a katana and thunder breath.

Nakime holds the position of Upper Moon Four. She can control the Infinity Fortress, create and separate eye familiars, and teleport people.