Well, without more information about this 'sayonara novel', it's hard to say precisely. It could be a coming - of - age story where the main character has to say goodbye to their childhood innocence or a group of friends. It might also be a love story where two lovers part ways and the novel explores the pain and growth that follows this separation.
Sayonara fanfic could refer to fan - created fictional works that are related to the concept of 'sayonara' which means goodbye in Japanese. It might be fanfictions that deal with themes of parting, endings, or characters saying goodbye in a particular fictional universe.
Tanjiro might use his sense of smell to detect hidden threats. Since his sense of smell is super - enhanced, he could sniff out any demons or traps in the way of saving Rengoku. For example, if there are demons disguised as allies, Tanjiro would be able to tell by their scent.
Yes, in some fanfictions, Tanjiro is depicted as the reincarnation of Yoriichi. This concept adds an interesting layer to the story as Yoriichi was an extremely powerful and legendary figure in the original lore. The idea allows for new storylines where Tanjiro might inherit some of Yoriichi's skills or have a deeper connection to the past events related to Yoriichi.
Tanjiro's fate in the manga is that he ultimately passed away. This event was a significant part of the story's development and had a profound impact on the other characters and the overall plot.