Grimoire of Zero

is a Japanese light novel series written by Kakeru Kobashiri, with illustrations by Yoshinori Shizuma. The series began publication on February 10, 2014 by ASCII Media Works under their Dengeki Bunko publishing imprint.

The series won the Grand Prize in the 20th Dengeki Novel Prize.

The series has a sequel series from the same author and illustrator called. It was published under Kodansha's Kodansha Ranobe Bunko from August 2018.

Synopsis
In a world of constant war between humans and witches, there exist the "beastfallen"—cursed humans born with the appearance and strength of an animal. Their physical prowess and bestial nature cause them to be feared and shunned by both humans and witches. As a result, many beastfallen become sellswords, making their living through hunting witches.

Despite the enmity between the races, a lighthearted witch named Zero enlists a beastfallen whom she refers to as "Mercenary" to act as her protector. He travels with Zero and Albus, a young magician, on their search for the Grimoire of Zero: a powerful spell book that could be extremely dangerous in the wrong hands. During their journey, his inner kindness is revealed as he starts to show compassion and sympathy towards humans and witches alike, and the unlikely companions grow together.

Characters

 * Zero
 * Mercenary
 * Albus
 * Thirteen
 * Holdem

Grimore of Zero
The manga adaptation of the light novel: with art by Takashi Iwasaki. It was serialised in Dengeki Maoh and released under the Dengeki Comics NEXT from May 2015.

Grimoire of Zero: Nano!
A chibi spin-off of the light novel: with art by Yasuoka. It was serialised in Dengeki Maoh and released under the Dengeki Comics EX from October 2016.

Grimoire of Zero
An anime adaptation of the light novel, produced by Studio WHITE FOX, aired for 12 episodes between April 10, 2017 and June 26, 2017.

CAST:
 * Yumiri Hanamori as ZERO
 * Tsuyoshi Koyama as MERCENARY
 * You Taichi as ALBUS
 * Takehito Koyasu as THIRTEEN
 * Masayuki Katou as HOLDEM