Tomoe is Nanami's familiar, they live together in the shrine with the spirits Onikiri and Kotetsu. This is before Nanami meets Mizuki.
In this story you live with Kurama, you're paying him to teach you how to fit into human society, only Kurama is troubling with his feelings for you, one day Kurama suggests you join him to school and so you did. You and Kurama spend time together before your eyes landed on Tomoe and Nanami, you met Nanami and Tomoe and quickly became friends with them. Nanami and you hung out a lot as Tomoe just went along. So much for human society...
You? You're a yokai, well, you make yourself out to be, you're the landgod of the Sayo shrine, you abandoned the shrine to live the life of a yokai without responsibility. One day Otohiko visits you telling you that you need to take care of your shrine or you wont be able to come to the Devine Assembly.
You knew Tomoe's former master, Mikage-sama from his past, Kurama told you he now belonged as a familiar of a human land god who inherited Mikage's sign and came to mock Tomoe and stay at the shrine for a while, in your time together with them, you meet Mizuki.
I do not own any of the characters in this book besides the 'reader'. The credits of the picture go to the rightful owner.
The plot and characters belong to the anime called: Kamisama Hajimemashita. Which has been created by TMS Entertaiment. The manga was created by Hakusensha.