Earlier today Seven Seas Entertainment announced that they licensed two short story stories based on Kore Yamazaki's The Ancient Magus' Bride manga series. The stories are titled The Ancient Magus' Bride: The Golden Yarn and The Ancient Magus' Bride: The Silver Yarn. Seven Seas will release The Ancient Magus' Bride: The Golden Yarn on December 11th of this year, while The Ancient Magus' Bride: The Silver Yarn is slated for March 19th, 2019. Both releases will have both paperback and digital versions.
Both books are actually written by Yamazaki herself and other authors such as Yuichiro Higashide and Yoshinobu Akita. Mag Garden published The Ancient Magus' Bride: The Golden Yarn in Japan last September, and published The Ancient Magus' Bride: The Silver Yarn last October.
Check out the official trailer for the anime series down below:
Seven Seas Entertainment also publishes The Ancient Magus Bride manga series and describes the story as:
Chise Hatori has lived a life full of neglect and abuse, devoid of anything resembling love. Far from the warmth of family, she has had her share of troubles and pitfalls. Just when all hope seems lost, a fateful encounter awaits her. When a man with the head of a beast, wielding strange powers, obtains her through a slave auction, Chise's life will never be the same again. The man is a "magus," a sorcerer of great power, who decides to free Chise from the bonds of captivity. The magus then makes a bold statement: Chise will become his apprentice - and his bride!