Saiyuki Gaiden
Manga
Saiyuki Gaiden is a Japanese manga series that serves as a prequel to the Saiyuki series Kazuya Minekura wrote and illustrated. Saiyuki Gaiden began serialization in Square Enix's shōnen manga magazine Monthly GFantasy from May 1999 to February 2003 and continued serialization in Ichijinsha's josei manga magazine Monthly Comic Zero Sum from November 2003, and was then transferred to the publisher's shōjo manga Comic Zero Sum WARD. Serialization finished in May 2009, with its chapters collected in four tankōbon volumes. The manga tells a story that occurs 500 years before the main story.
Description from Wikipedia, available under CC BY-SA 4.0. May be shortened.