What is this, then?

A listing of youkai passed down in our family, you could say.

Ah.

Which means...

We're using this to look for our next project?

Bingo!

By the way, this one was written by the ninth Child of Miare, Akyuu.

Child of Miare?

The Children of Miare are said to be reincarnations of Hieda no Are, who never forgot anything she once saw or heard.

Supposedly they also inherited that same ability of Are's, called gumonji. Using that ability, they left behind these books for future generations.