Boku no Sekai wo Mamoru Hito EX

is the extra volume of the Boku no Sekai wo Mamoru Hito light novel series, written by Nagaru Tanigawa and Illustrated by Akifumi Orizawa. It was released under the Dengeki Bunko Imprint in November 2006.

Synopsis
An ordinary high school student, Asanagi Tatsumi, was escorted by a self-proclaimed "Tatsumi's younger sister" and actually a humanoid weapon-Nekoko and a self-proclaimed "Tatsumi's guardian" and actually a fairy-Ayaba. Please enjoy the fun daily life such as Tatsumi-kun & 2 beautiful girls & pleasant friends weaving, opening the pool, pounding cooking training, etc. ♪

(source: Bookwalker JP - Translated)