Yuuki Yuuna wa Yuusha de Aru: Yuusha-shi Gaiten (結城友奈は勇者である 勇者史外典, lit. Yuuki Yuuna is a Hero: Hero History Apocrypha) is a 3-part spin-off light novel based on Nogi Wakaba wa Yuusha de Aru.
Parts (in order):
Uesato Hinata wa Miko de Aru (Uesato Hinata is a Miko)