Franchise context: The write-up below is from the parent franchise article (anime, book series, or IP) rather than the card game itself. A dedicated CCG profile has not been written yet.
Kekkaishi is a Japanese manga series written and illustrated by Yellow Tanabe. It was serialized in Shogakukan's shōnen manga magazine Weekly Shōnen Sunday from October 2003 to April 2011, with its chapters collected in 35 tankōbon volumes. The series is about Yoshimori Sumimura and Tokine Yukimura, heirs to rival families of kekkai users, who must defend their school from the spirits drawn to the sacred land upon which it is built.
Source: en.wikipedia.org/wiki/Kekkaishi