Kimetsu no Yaiba: The Flower of Happiness

Kimetsu no Yaiba: Flower of Happiness (鬼滅の刃: しあわせの) is the first light novel series from the Kimetsu no Yaiba (Manga) written by Aya Yajima.

Synopsis
There are five chapters in total, as well as an afterword.

Chapter 1: Flower of Happiness (しあわせの {{Ruby|花|はな}})
Ten days following the events of the Drum House Arc, the group is seen staying at the Wisteria House belonging to Hisa. While in her care, the group is informed of a wedding which is going to occur, and are invited to give their blessing. Following the wedding, the group overhears two girls speaking of the "Flower of Happiness", which is said to bestow happiness to whoever finds it. Tanjiro becomes intrigued with the rumor, and sets out to find the flower for Nezuko's sake.

Chapter 2: For Whose Sake ({{Ruby|誰|だれ}}が{{Ruby|為|ため}}に)
Following the events of the Natagumo Mountain Arc, the group is now staying at the Butterfly Mansion. At night, Zenitsu takes Nezuko out on a walk to a nearby flower patch, and reminicies on the memories of his training. During one instance, he escaped his lesson and discovered a girl crying in the forest. Upon asking what's wrong, the girl named Sayuri reveals that she has been offered to a nearby Demon by her step-father, as a sacrifice for her family's protection. Outraged, Zenitsu sets off to locate and defeat the Demon in order to protect Sayuri.