Natsume Reiko is a fictional character from the manga and anime series Natsume's Book of Friends (Natsume Yūjin-chō). She is known for her ability to see youkai and spirits, which she inherited from her grandmother. Reiko is a kind and gentle person who often helps these supernatural beings, forming connections with them. Reiko's most notable achievement is the creation of the Book of Friends, a collection of names of youkai and spirits she encountered. By writing their names in this book, she granted them protection and friendship. Her legacy significantly impacts her grandson, Natsume Takashi, who continues her work in the series.