Ayakashizou no Kanrinin

Suddenly, her parents traveled abroad, and Aoma Kohinata, a high school student who remained alone in Japan, decided to live with writer named Kiyoto Yuzuki. On the evening of the day she moved to the old mansion where Yuzuki lives, Soma suddenly meets a lovely little demon. In fact, in the garden of Yuzuki's house, there is a warehouse connected to the world of Ayakashi, and Yuzuki was the manager of that warehouse! From that day onward, the friendly youkai who began to gather around Soshin. However, strangely, the youkai seem to be familiar with Aoma when he was young. Source: MU