This a manga by Koyoharu Gotōge published by Shonen Jump in February 2016. The series will presumably reach 23 volumes although the greatest success has come from the anime.
Takes place in the Taisho Era in Japan. Tanjiro's family is killed by an Oni except for him and his sister Nezuko who has been transformed into a demon although only in part. Nezuko continues to demonstrate human attitudes and rational thinking. It won't take long for Tanjiro to be recruited as a demon slayer to find a way for his sister to regain her human form.