結界師 [kekkaishi] (Barrier Master) is a shounen anime and manga series by 田辺イエロウ (Tanabe Yellow). In 2007, Kekkaishi was awarded the Shogakukan Manga Award in the Shounen-style category. Tanabe gratefully thanked "everyone who supports Kekkaishi" and that this award was only made possible by "the people who enjoy [her] manga."[1]
The Karasumori household was protecting the land. They were known for their outstandingly high levels of spirital energy. Due to that, they were always troubled by mysterious things and incomprehensible phenomena. That's why an expert in eliminating ayakashi (demon spirits) was called in. That was the founder, Hazama Tokimori. After that, he became the personal Kekkaishi of the Karasumori household.
However, after a long time, the Karasumori family stockpiled a great shell of the energy. All the ayakashi that got close to it rapidly transformed and began to hurt people. One day, exhaustion and grave illness overcame the Kekkaishi, adn he could no longer continue his job. On the morning of the fourth day, when the Kekkaishi came back out, the castle had changed. It was filled with enlarged ayakashi, and there were no humans left alive. This is how the Karasumori household fell. The shell, that was the source of the karasumori household's energy, now sleeps deep under the school built on the remains of the karasumori land. However, that power is stil present, and leeting it reamin undisturbed causes all ayakashi that get near it to transform and become dangerous. That is, here, at Karasumori Academy.
Kekkaishi, experts at exterminating monster. Sumimura Yoshimori and childhood friend and neighbor, Yukimura Tokine, have taken over a job passed down from many generations to protect the ayakashi-infested land of Karasumori. However, the Sumimura and Yukimura households have fought for over 400 years over which is the true legitimate successor to the powerful Hazama Tokimori.[2]
Sumimura Yoshimori (墨村良守)
Fourteen-year-old Yoshimori is a junior high school at Karasumori Academy. He's 
lazy, late to class, and always to blunt of his classmates' jokes. However, they do not know that he is a kekkaishi who protects the land from ayakashi. Yoshimori does not take his job seriously constantly fights with his grandfather about it. He'd rather be in the kitchen, cooking sweets and cakes for his crush and childhood friend, Tokine. However, when his mistakes and carelessness causes Tokine to be severely injured, Yoshimori becomes determined to protect her and never let her get hurt again. Through training and determination, he gradually learns how to control his power ... but he's just not quite there yet. He's brash, quick to anger, and as conspicuous as you can get; still, there's something about him. He's accompanied by his insulting demon-dog, Madarao.
Yukimura Tokine (斑尾)
Sixteen-year-old Tokine is the heir to the Sumimura clan. She is an intelligent and 
model student, who is praised by her classmates and teachers for her grades and her kind personality; the model student at Karasumori. Tokine seems to notice Yoshimori's feelings towards her, though she does quite understand them completely. When he gives her sweets to eat, she refuses to show him just how good it is and chastises him for not focusing his energy into his kekkaishi work. As a kekkaishi, Tokine is a skill tactician and strategist. She clearly understands the limits of her power and, instead, verses herself in techniques and control. She comes to notice Yoshimori's growing power but is still frustrated by his lack of control and low-accuracy, much to her dismay. Tokine is accompanied by her family's demon-dog Hakubi who calls her "honey."
Kekkaishi use six basic techniques when capturing and destroying ayakashi:
However, Kekkaishi have the potential to create much more than just barriers or use variant kekkai techniques.
[1] Kekkaishi wins 52nd Shogakukan Manga Award. Anime News Network.
[2] Kekkaishi. Wikipedia.org.