Kyōran Kazoku Nikki (狂乱家族日記, The Diary of a Crazed Family) is a light novel series by Akira (日日日), with illustrations by x6suke.

A thousand years ago, Enka (閻禍), the god of destruction, died saying that its "child" would destroy the world.

In order to prevent this, the Great Japanese Empire Paranormal Phenomena Bureau of Measures begins "Operation Cozy Family" (なごやか家族作戦, Nagoyaka Kazoku Sakusen) (code name: "code-Olympus").

The goal of the operation is to discern which child the prophecy applies to, as well as to teach him or her about the love of family in hopes of convincing him or her to not destroy the world.

The story focuses on the mishaps and adventures that the ad hoc family experiences together.