Tanjiro, the main character of the anime/manga series Demon Slayer: Kimetsu no Yaiba, does not become a demon himself.
In the series, Tanjiro Kamado is a young boy who becomes a demon slayer after his family is brutally murdered by demons, with his younger sister Nezuko being the only survivor, but turned into a demon in the process. Tanjiro’s ultimate goal is to turn Nezuko back into a human and avenge his family.
Throughout the series, Tanjiro develops exceptional swordsmanship skills, as well as unique breathing techniques that enhance his physical abilities and enable him to fight demons more effectively. He also gains the support of other demon slayers and allies, who help him in his quest.
Despite encountering many demons throughout his journey, Tanjiro remains human and steadfast in his mission to protect his loved ones and defeat the demons who threaten them. He also maintains his compassion and empathy towards those who have been turned into demons, as he sees them as victims of a cruel fate and seeks to save them if possible.
It is worth noting that there are several characters in the series who have become demons through various means, such as Muzan Kibutsuji, the main antagonist of the series, who is the first demon and has the power to turn humans into demons by infecting them with his blood. However, Tanjiro does not fall victim to this fate and remains a human, fighting alongside his allies to protect humanity from the threat of demons.
In conclusion, Tanjiro does not become a demon in the Demon Slayer: Kimetsu no Yaiba series. He remains a human character who develops exceptional skills and techniques to fight demons and protect his loved ones. His unwavering determination and compassion make him a beloved and inspiring character in the series.