The novel contains various side stories which shed more information on the characters that show up in the Nurarihyon no Mago novel. It can be seen as a complement to further understand the Nurarihyon no Mago universe.
Volume 1: Nurarihyon no Mago: Obscure Tales of Ukiyoe Town
Volume 2: Nurarihyon no Mago: The Story of Edo's Nura Gumi