Hokago Hyaku Monogatari

is a Japanese light novel series written by Hirokazu Minemori, with illustrations by Shin Kyogoku. The series began publication on February 10, 2008 by ASCII Media Works under their Dengeki Bunko publishing imprint.

The series won the Grand Prize in the 14th Dengeki Novel Prize.

Synopsis
"Suddenly bad, but can you suck your blood?"

Shinichi, a high school student and an art member, meets a strange girl at school at night when she returns to pick up her forgotten items.

The girl is very beautiful, but her eyes are shining silver, and she wants to suck Shinichi's blood.

Shinichi, who escaped the difficulty by seeing the girl's identity as "Itachi", makes a certain promise with her insanely ....

The next day, a weasel girl appeared in the art room.

According to him, this school is prone to youkai, and Shinichi is easy to attract them, so he came to fulfill his promise before it was too late.

Itachi will protect Shinichi until he fulfills his promise.

At the suggestion of Misaki, a youkai enthusiast who is a senior in the art club, Itachi will be welcomed into the art club.

And, as Itachi said, various youkai began to appear at school ...

It's a mysterious after-school story about a pure cute Itachi and an ordinary high school student Shinichi.