The Twelve Kingdoms is a series of fantasy novels written by Japanese author Fuyumi Ono and illustrated by Akihiro Yamada. The first entry in the series called The Twelve Kingdoms: Sea of Shadow was published by Kodansha in Japan in 1992; the last Kodansha volume was released in 2001. In 2012, the series was resumed under the Shinchō Bunko line from Shinchosha. Shinchosha has also begun reprinting the older volumes with new cover and interior art from Akihiro Yamada. The first new publication of the series in six years was released in 2019.

Pierrot Co., Ltd. is a Japanese animation studio established in May 1979 by Yuji Nunokawa, previously an animator and director for Tatsunoko Production. Its headquarters are located in Mitaka, Tokyo. Pierrot is renowned for several worldwide popular anime series, such as Naruto, Bleach, Tokyo Ghoul, Yu Yu Hakusho, Black Clover, Boruto: Naruto Next Generations, Ghost Stories, Great Teacher Onizuka, and Saiyuki.