Ga-Rei Series by Hajime Segawa

Freshman Nimura Kensuke has the ability to see ghosts, and his life changes when he meets Kagura, a girl with the power to summon a "Ga-Rei" called Byakuei. The two work together to find evil spirits and devour them with the Ga-Rei under the auspice of the Ministry of the Enviroment's Supernatural Countermeasure Division.

Non-stop after-school spirit-fighting action!The battle heats up quickly as Yomi plans to revive an immortal creature sleeping below the city and the Agency races to stop her. Kensuke joins the fight to assist Kagura, but is he leaving his greatest weakness wide open?

The mortal struggle with Yomi ends at last! A new twist in the tale!Yomi has embedded a sesshoseki, a deadly spirit crystal, in Kensuke's very flesh. Frantic for Kensuke's well-being, Kagura confronts Yomi at the risk of her own life. And when the life-or-death struggle shudders to a halt, a mysterious child appears... This is after-school spirit-fighting action at its best!