Kono Subarashii Sekai Ni Bakuen O! Zoku (Light Novel)

Kono Subarashii Sekai ni Bakuen o! is a spin-off to the main KonoSuba series. Written by Natsume Akatsuki and illustrated by Kurone Mishima, it's set around a year before the main series and focuses on the previous life of Megumin.
Inspired by the Silver Haired Thieves, Megumin decides to set up her own band, but her only members are an unworldly princess and a dangerous fellow magician!
Notice: This light novel is written in Japanese.