The Familiar of Zero is written by Noboru Yamaguchi and illustrated by Eiji Usatsuka. It was first published in 2004. The series is still going strong with 20 volumes and counting. There have been four anime series based of the novels, each 12 episodes long. There are two light novel spin offs. Three manga based on it and an OVA. Also, there have been four games based on the series as well.