Makai Kizoku no Natsu Yasumi

is a Japanese light novel series written by Jo Aikawa, with illustrations by Gintaro. The series began publication on July 10, 2015 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
Play games from the morning to catch bugs and fish. However, it's just summer vacation.

Summer vacation from tomorrow. It was supposed to be cute but no boyfriend history = Karin of age has no plans. Until I met them. A strange young man and a companion girl fighting at a bus stop. Anthem, a young man in an old-fashioned costume, is said to be a nobleman who came to vacation from the demon world.

A group of anthems sitting at Karin's house. Begin to enjoy insect picking, TV games, and summer vacation like an elementary school student. When an empty country town goes with Anthem and others, it becomes a wonderland for some reason. Wherever anthems play with all their might, using their magical powers in vain, there is always a turmoil !?