Tenen Jakko

Twin Star Exorcists: Tenen Jyakko (双星の陰陽師 ―天縁若虎―) is the first official novel, written by Hajime Tanaka and supervised by Yoshiaki Sukeno.

Extra Manga
This extra is called 天縁若虎～二色滑稽画之序～, which is published at Jump SQ, Issue August 2016, and is included in the novel.