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 Breathing is also a reflection of his gentle nature. Like all Breathing techniques, Water Breathing has destructive capabilities, but it's also the only Breathing technique that is seemingly capable of giving demons a peaceful death.

Even in his position as a Demon Slayer, Tanjiro rarely dehumanizes demons or harbors malicious intent toward them. This is partly because Nezuko, his sister, is a demon that he wishes to change back into a human. This aspect of his personality mirrors how he uses his Water Breathing techniques in the Mount Natagumo arc of the Demon Slayer anime. When in a duel with the Mother Spider Demon, the demon realizes that death could be a better fate than life and therefore, she ceases fighting. Offering her life, Tanjiro switches to Water Breathing, Fifth Form: Blessed Rain After The Drought. This technique is intended to be used as a form of mercy kill - something that is clearly true, as the Mother Spider Demon compares it to "warm rain," and then says, "I never dreamed my end would be this tranquil."

Tanjiro remains very capable of killing demons without hesitation, but it's fitting that the first Breathing technique he learns gives him the opportunity to kill demons as peacefully as possible. This acts in line with his merciful nature that he extends to demons, as well as humans. Furthermore, it reflects his primary motivation in the series - to save Nezuko, a demon. As such, it shouldn't be a surprise that Tanjiro learns Water Breathing before Sun Breathing. Although his mentor exercises Water Breathing, learning this technique first allows Tanjiro to retain his calm, gracious nature. In contrast, if he had learned Sun Breathing first, he may have harnessed his power too quickly, and would not have been able to inflict mercy killings when he sees fit. Tanjiro is yet to master Sun Breathing in Demon Slayer, but it's suitable for his character that he masters Water Breathing first.

Next: Demon Slayer: Why Tanjiro's Earrings Were So Controversial