Kekkaishi (結界師, Kekkaishi? literally "Barrier Master") is a manga series by Yellow Tanabe. It is published in Japan by Shogakukan and in North America in English by Viz Media. It was adapted as a 52-episode anime series by Sunrise broadcast between October 2006 and February 2008. The series is about teenagers Yoshimori Sumimura and Tokine Yukimura, heirs to rival clans of kekkai (barrier magic) users, who must defend their school from the spirits drawn to the sacred land it is built upon. Kekkaishi received the 2007 Shogakukan Manga Award for shōnen manga.
Five hundred years ago, a feudal lord was attacked by demons wanting to retrieve his mysterious inner power, the invincible power that can help them take over the human world. The famous mage, Tokimori Hazama, was called upon, and with his 2 students, managed to save the whole land. But they fell ill, the feudal lord was killed, his power was also buried with him at a site called Karasumori.
In the present day, Yoshimori Sumimura and Tokine Yukimura, heirs of the Hazama clan, became the kekkaishi protecting the land and the power. They use a technique called Kekkai, a form of magical barrier, used to capture and destroy Ayakashi (monsters/demons) that are drawn to this land. Any demons that come near the power will become stronger and therefore Yoshimori and Tokine are to guard the land from intrusion of the Ayakashi.
But some of the demons form a powerful organization to take over that mysterious power. Yoshimori plans to destroy not only the demons, but also to gain the power to completely save the world from being controlled by demons. To do that, he first needs to know what the power actually is, and also strengthen his poor kekkai skills.