Tanjiro Kamado, eldest son of a charcoal-selling family, saw his life irrevocably shift when the demon Muzan Kibutsuji slaughtered his kin. His sister Nezuko survived but became a demon, driving Tanjiro to join the Demon Slayer Corps for her cure and vengeance. Trained by Sakonji Urokodaki on Mount Sagiri, he mastered Water Breathing through rigorous conditioning and swordsmanship lessons from Urokodaki’s spirit-bound former pupils. After two years, he conquered the Final Selection survival trial against demons, defeating the Hand Demon—a victory that transformed his forehead scar into a flame-patterned Demon Slayer Mark. Wielding a rare black Nichirin Sword, signifying adaptability to multiple Breathing Styles, Tanjiro built his combat foundation on Water Breathing before integrating his family’s Hinokami Kagura (Dance of the Fire God). This technique, revealed as Sun Breathing—the original and most potent style against Muzan—became pivotal. His extraordinary sense of smell detected emotions, tracked demons, and anticipated attacks. Rising from Mizunoto to Hinoe rank, he defeated Lower Moon Five Rui, Lower Moon One Enmu, and Upper Moon Six Gyutaro and Daki, often alongside allies like Hashira. Despite power rivaling the Hashira after mastering Sun Breathing, he never formally joined their ranks due to Corps rules requiring solo defeat of a Twelve Kizuki member at Kinoe rank, and the Corps’ disbandment post-Muzan. During the Hashira Training Arc, Tanjiro endured specialized regimens: Tengen Uzui tested endurance, Mitsuri Kanroji flexibility, Muichiro Tokito speed, Obanai Iguro sword skills, Sanemi Shinazugawa pounding training, and Gyomei Himejima muscle building. This honed his prowess, though full Sun Breathing mastery eluded him. In the final battle against Muzan, Tanjiro lost his right eye and left arm. Nearing death, Muzan transformed him into a demon king, granting enhanced regeneration, fangs, slit pupils, and additional flame marks. Tanjiro resisted harming Nezuko before collective efforts reverted him to human, leaving permanent blindness in his right eye and a withered, insensate left arm. Profoundly kind and empathetic, Tanjiro prayed for defeated demons’ souls, believing remorseful ones deserved dignity but showing no mercy to atrocity-committers—a philosophy shaped by Nezuko’s state and his trauma. Yet injustice ignited cold ruthlessness, particularly against Muzan and demons harming innocents. His rural honesty sometimes rendered him naive in cities. After Muzan’s defeat and the Corps’ dissolution, he married Kanao Tsuyuri in a demon-free world, adapting to his injuries as an emblem of hard-won peace.