Zaregoto is a Japanese light novel series written by Nisio Isin and illustrated by Take. The series was published in Japan between February 2002 and November 2005 by Kodansha Books in nine volumes. Celebrating the twentieth anniversary of Nisio's debut in 2022, the tenth volume of the series was released on February 8, 2023. It was then followed by a seven-volume spin-off series also published by Kodansha Books, the Ningen series, focusing on the Zerozaki clan. A second spin-off series focused on Jun Aikawa titled Saikyō series was serialized in the Mephisto magazine, and was collected by Kodansha in five volumes. First two volumes of Zaregoto were initially released in North America by Del Rey Manga, but have since been republished by Vertical, who also released the third volume. An eight-episode original video animation series adaptation of the first volume by Shaft was released between October 2016 and September 2017.

Shaft, also known as Shaft Animation Studio, is a Japanese animation studio headquartered in Suginami, Tokyo, and founded in 1975. Since 2004, the studio's productions have been broadly influenced by director Akiyuki Shinbo, whose visual style and avant-garde cinematography are featured in works including Hidamari Sketch (2007), Sayonara, Zetsubou-Sensei (2007), the Monogatari series (2009–present), Puella Magi Madoka Magica (2011), Nisekoi (2014), and March Comes In Like a Lion (2016).