Tanjirou Kamado

The protagonist of this work. His age progresses from 13 to 15 years old. His height grows from 156 cm to 165 cm, and his weight from 53 kg to 61 kg. He is the eldest son of the charcoal-making Kamado family, and is a family-loving boy whose father has died at the start of the story. He is characterized by a scar on the left side of his forehead, and floral card-style earrings that feature sun motifs. The scar on his forehead originally came from a burn when he defended his younger brother as a child, becoming more prominent during a fight against the Hand Demon in the Final Selection, and changing to a flame-like scar after the battles against Daki and Gyutaro, marking him as a true chosen one. He is a "Child of Bright Red," with hair and eyes tinged in red, which is considered a good omen for families involved in fire-related work. He is stubborn, hard-headed in two senses of the word, and overly serious which sometimes results in socially awkward behavior.

He has an extraordinarily keen sense of smell, capable of sensing even the emotions of others. This becomes a strategic advantage in battle, where it evolves into the ability to visualize "threads of openings" after training. He can differentiate humans from demons through scent, and utilizes it to identify his archenemy, Muzan. He also displays excellent intuitive fighting skills and flexible thinking in combat.

Despite his combat skills, he is incredibly kind-hearted and finds it difficult to be ruthless, even towards demons. He openly criticizes the merciless nature of the Demon Slayer Corps, which leads him to be regarded as a heretic by his peers.

He wears a checkered haori over his corps uniform and carries a special box, made of cloudy cedar wood by Urokodaki, on his back in which he transports Nezuko. His current priority is to defeat the Twelve Kizuki and deliver their blood to Tamayo.

On his way back from selling charcoal, he stays overnight at Saburo's house, and during his absence, all his family members except Nezuko are killed by Muzan. To turn Nezuko, who barely survived as a demon, back into a human, Tanjirou visits Urokodaki’s place, introduced by Giyu Tomioka. Seeking the power to pursue demons, he trains for two years and masters "Water Breathing." He later adapts the "Dance of the Fire God," a traditional Hinokami Kagura dance taught in his family, into a sword fighting technique during his battle with Lower Moon Five, Rui.

His swordsmith is Haganezuka and the color of his Nichirin Sword is a deep black with a hilt and sheath that are primarily black and silver, including an openwork tsuba reminiscent of the sun. His mastery of Water Breathing doesn’t align well with his attributes; the physically demanding moves of Hinokami Kagura surpass his body's limits. Aware of these limits, he develops a new, hybrid breathing technique that combines Water Breathing's movements with Hinokami Kagura during his fights against Daki and Gyutaro. His swords frequently shatter or get lost in fierce battles. The most recent sword is one from the Sengoku period stored inside Tsugikuni's Zero Type unit, which was sharpened by Haganezuka. Its tsuba is a relic from Kyojuro Rengoku.

In the Infinity Castle, he fights Upper Moon Three, Akaza, alongside Giyu, and after a daunting struggle, he manages to grasp the "Transparent World" and narrowly defeats Akaza.

In the battle against Muzan, he labels the Demon Slayer Corps as “a gathering of aberrations” and the slain victims as having "met a great disaster." Showing no emotion, Tanjirou vehemently declares Muzan as a creature that shouldn't exist, fighting him with his peers including the Hashira, although he loses his right eye and left arm to Muzan’s ferocious attacks. However, after dreaming and discovering the truth about the Hinokami Kagura, he successfully defeats Muzan after an arduous struggle. As Muzan approaches death, he misinterprets a phrase by Yoriichi Tsugikuni — "Feelings are indestructible and eternal" — pouring his own blood and power into Tanjirou, turning him temporarily into the "Demon King." Although he initially turns against his allies, Nezuko’s desperate calls and a demon-to-human cure thrown by Kanao eventually turn him back to a human.

After the war, he settles his affairs, visits the graves of fallen comrades, and returns to live with Nezuko, Zenitsu, and Inosuke at his family home. His right eye and left arm, though regenerated when he turned into the Demon King, do not recover their senses and suffer lasting effects.

Originally intended as a side character for "Demon Slayer," the character was promoted to the protagonist after an initial rejection of the drafts. Gotouge reshaped the character into “a coal-selling boy who joins the Demon Slayer Corps in a bid to turn his demon-turned sister back into a human after his family is killed,” which the editor saw as a character “burdened with fate.”