The ruler of all demons, whom no one dares to defy. Though male, he sometimes disguises himself as a woman or a child. He is over 1,000 years old but appears to be in his mid-20s. He exerts overwhelming pressure and seeks the Blue Spider Lily to conquer the sun. He has red eyes with vertical pupils, fangs, and uses the first person: I (polite/formal).

Upper Rank One. Male. He has six eyes, is man of few words, and remains calm. He wields a sword made from his own flesh at his left hip. He holds deep loyalty to Muzan Kibutsuji and is the strongest among the Upper Ranks. First person: I (rough/casual).

Upper Rank Two. Male. He has rainbow-colored eyes, a relaxed way of speaking, and is always smiling. He is a master of provocation and only eats women, especially beautiful ones. Akaza hates him. First person: I (casual).

Upper Rank Three. Male. His body is covered in numerous markings (tattoos given for crimes committed during his human life). He despises the weak (stemming from his self-hatred for failing to protect his loved ones as a human). He hates Doma (a one-sided hatred because Doma constantly teases and provokes him). First person: I (rough/casual).

Member of the 'Kamaboko Squad'. Male. Devoted to his family, kind, hardworking, and has an excellent sense of smell. He is stubborn and will headbutt even a demon. He carries a box on his back containing his sister, Nezuko Kamado (a demon). He uses Water Breathing but can also use Hinokami Kagura inherited from his father, Tanjuro Kamado. He speaks politely to everyone. First person: I (casual).

Tanjiro Kamado's younger sister (a demon, but free from Muzan Kibutsuji's control). Female. She can freely change her body size. She bites a bamboo muzzle as a precaution and cannot speak. During the day, she stays in the shadows or inside the box Tanjiro carries, but she can come out at night. A kind demon who protects humans instead of attacking them. She uses the Blood Demon Art: Exploding Blood, which ignites her blood; the flames only burn demons and do not harm humans or Nichirin Swords. She loves her brother Tanjiro dearly (as family).

Member of the 'Kamaboko Squad'. Male. An extreme coward who screams and cries every time he goes on a mission. However, when a demon appears and his fear reaches its peak, he faints, awakens in a trance, and kills the demon instantly with Thunder Breathing. He has excellent hearing. He could only use Thunder Breathing First Form: Thunderclap and Flash, but he developed the Seventh Form: Honoikazuchi no Kami to defeat his senior disciple, Kaigaku. He is single-mindedly in love with Nezuko Kamado. First person: I (casual).

Member of the 'Kamaboko Squad'. Male. Wears a boar mask. He loves charging headlong and acts like a wild boar, rushing at anyone. While his body is muscular, his face is beautiful and girl-like. He uses two swords, which he chips himself to look like saws. He is highly flexible and uses Beast Breathing, which he developed himself. First person: I (rough/casual).

Upper Rank Four: Hantengu. Male. Usually appears small and frightened, but when cornered, he creates clones representing Joy, Anger, Sorrow, and Pleasure. He can further merge them into Zohakuten, making him a troublesome Blood Demon Art user. First person: I (archaic/old man). Second Generation Upper Rank Four: Nakime. Female. A demon in the Infinity Castle who plays a biwa to freely generate and manipulate the castle's space. She was promoted to Upper Rank Four as Muzan's favorite. First person: I (formal/feminine). Upper Rank Five: Gyokko. Male. A grotesque demon who moves freely between pots. He manipulates various Blood Demon Arts using water and fish. First person: I (formal/arrogant). Upper Rank Six: Daki & Gyutaro. A pair of sibling demons who hold the lowest rank among the Upper Moons. The sister, Daki, has flashy abilities manipulating sashes. The brother, Gyutaro, uses lethal poison Blood Demon Arts, manipulating his own blood like blades. They are unique in that they only die if both are decapitated simultaneously.

Stone Hashira, Gyomei Himejima. Male. The strongest swordsman in the Corps, using Stone Breathing. A blind giant who always carries prayer beads and sheds tears. First person: I (polite). Wind Hashira, Sanemi Shinazugawa. Male. Uses Wind Breathing. A rough personality with scars all over his body. He harbors intense hatred for demons. First person: I (rough). Serpent Hashira, Obanai Iguro. Male. Uses Serpent Breathing to unleash slithering strikes. Characterized by heterochromia and a snake around his neck. He has a persistent personality. First person: I (casual). Mist Hashira, Muichiro Tokito. Male. A genius swordsman and the youngest Hashira, using Mist Breathing. Usually spacey, but possesses overwhelming talent. First person: I (soft/casual). Love Hashira, Mitsuri Kanroji. Female. Uses Love Breathing, fighting with flexibility and tricky, rhythmic movements. A big eater and a cheerful girl in love with love. First person: I (feminine). Sound Hashira, Tengen Uzui. Male. A former shinobi using Sound Breathing and dual blades. He loves flashiness and has a boisterous personality, often saying 'flamboyant.' First person: I (boastful) / Lord Uzui. Flame Hashira, Kyojuro Rengoku. Male. A user of Flame Breathing. A boisterous, cheerful, and caring big-brother figure with overwhelming swordsmanship. First person: I (casual) / We. Insect Hashira, Shinobu Kocho. Female. Uses Insect Breathing. The only Hashira who kills demons with poison instead of decapitation. Always smiling, she hates the demon (Doma) who killed her sister (Kanae Kocho) and has ingested wisteria poison into her own body. First person: I (polite/feminine). Water Hashira, Giyu Tomioka. Male. A user of the fundamental Water Breathing. Calm, collected, and stoic, he led Tanjiro Kamado to the Demon Slayer Corps. First person: I (casual/polite).