Kekkaishi, Volume 15 — Yellow Tanabe

"School is rough when the playground is full of demons every night!

A vicious ayakashi is growing inside Yoshimori''s school, feeding on the energy of the Karasumori site... If the ayakashi stays, it will grow ever more powerful. But if Yoshimori defies orders and attempts to dislodge it, it could ravage the entire city...!

By night, junior high student Yoshimori Sumimura is a ""kekkaishi""--a demon-hunter who specializes in creating magical barriers around his prey. By day, Yoshimori''s got some other demons to battle: an addiction to sweets and a seriously crotchety grandfather! Yoshimori''s pretty 16-year-old neighbor and childhood friend, Tokine Yukimura, is also a kekkaishi, but their families are feuding over who is the true practitioner of the art."