Wagaya no Oinari-sama.

Wagaya no Oinarisama (我が家のお稲荷さま., lit. "Our Home's Fox Deity") is a Japanese light novel series by Jin Shibamura, with illustrations by Eizō Hōden. The first novel was released in February 2004, and as of October 2007, seven volumes have been published by ASCII Media Works under their Dengeki Bunko imprint.

Plot
The Mizuchi bloodline has long been hunted by Yokai, or monsters. Toru and Noboru Takagami are descendants of this bloodline, and under their grandmother's discretion, are given a secret weapon to combat these monsters. It is Kugen Tenko, a fox deity who can take the shape of a man or woman at will. The mischievous deity is accompanied by a shrine maiden, Ko, who will both live with the Takagami brothers at their house. Life just got complicated.