Kekkaishi follows Yoshimori and Tokine, the two inheritors of the Sumimura and Yukimura families, tasked with the job of protecting the powerful and mysterious land Karasumori. Karasumori has the ability to attract ayakashi or demons and if these ayakashi are neglected, they grow stronger with every second they stay in Karasumori.
The whole series starts off in an episodic manner, every chapter is a fight with the ayakashi, however even in these fights, the characters grow. They mature and learn to improve themselves mentally, as mental strength is the fuel for the Kekkai technique. Yoshimori, initially starts out as a impulsive and ignorant kid, his only goal in mind is to protect his childhood friend. He doesn't care much for his duty to the land nor understands fully the responsibility he's been tasked with. However he changes, he starts to sympathize and connect more with all the characters around him and realizes what he must do in order to truly protect those around him.Tokine, by no means is weak. She is smart, calm and collected and serves as a foil to Yoshimori's brash and reckless nature.
I really loved this manga. Yoshimori's cake loving attitude and quick temper make him a really good source of comedy in this manga. The art, creativity and panel approaches, really set the scene and atmosphere and make the manga really enjoyable. The characters, I felt were all thoroughly developed. We understand why every character takes the actions that he or she takes, and can empathize with them. The characters aren't just "powered up" in their power abilities. Rather, a series of mental trainings and maturity is what leads to growth and true strength in this manga.
A lot of people were complaining about the ending. For me, the ending was fitting to the story, Yellow really did finish it all alright. The ending did have a bitter taste to it, and it seemed as if the goofiness that was in the first half simply vanished during the second half- it was occasionally there, but those instances were just simply too rare. But even so, I think that just ended up intensifying the approach of the end of the story. So I liked the ending too.