The emotional toll of slaying on Tanjiro and his friends in the anime series "Demon Slayer: Kimetsu no Yaiba" is significant. Throughout their journey as demon slayers, they face constant danger, loss, and trauma. Tanjiro specifically experiences immense grief over the loss of his family and struggles with the burden of seeking revenge while also trying to protect others. His friends, such as Zenitsu and Inosuke, also grapple with their own emotional challenges, including fear, self-doubt, and the weight of their responsibilities as demon slayers. Overall, the emotional toll of slaying takes a heavy toll on Tanjiro and his friends, shaping them and their relationships as they continue their fight against demons.