As a Demon Slayer, Tanjiro Kamada must master breathing techniques with his Nichiren sword to kill demons, but Tanjiro's first breathing style in Demon Slayer has a hidden meaning beyond practicality. Tanjiro Kamada begins training to become a Demon Slayer after his family is wiped out by a Muzan Kibutsuji, and his sister Nezuko is transformed into a demon. Despite the tragedy inflicted upon him and his family, Tanjiro always retains a kind heart, and can often sympathize with the demons that it is his duty to eliminate.
Prior to the final selection, Tanjiro is trained by Sakonji Urokodaki, at the behest of the Water Hashira, Giyu Tomioka — the Hashira being the strongest Demon Slayers in the verse. Urokodaki is a retired Demon Slayer, who used to be the Water Hashira. Thus, he trains Tanjiro in Water Breathing techniques early in his journey. As Tanjiro develops, he uncovers Sun Breathing techniques, namely the Hinokami Kagura. Tanjiro first unleashes this technique against Rui, a spider demon that is a lower rank of the Twelve Kizuki. The mysterious Hinokami Kagura is a technique passed down throughout generations, and the secrets of the power of Sun Breathing linger in Tanjiro's lineage. Despite Tanjiro's innate connection to this breathing technique, there's a good reason why it's not the first that he learns to use to fight.
Related: Demon Slayer: Zenitsu's Sword Abilities & Powers Explained
Since Giyu is the reason that Tanjiro became a Demon Slayer, and Giyu introduced him to Urukodaki, Tanjiro was always going to learn Water Breathing first. While this makes practical sense — and in the Demon Slayer universe, Water Breathing is supposedly the easiest breathing technique to learn — Tanjiro's connection to Water
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