Nue's Exorcist, Vol. 1

Outcast Gakuro Yajima's only goal in life has been to avoid spirits and try to live in peace. One day, he accidentally enters a sealed room and meets Nue, a quirky spirit who asks him to defeat the evil ones roaming his school. Gakuro is reluctant to take her up on the offer, but the spirits won't be waiting patiently for him to make up his mind…

Volume 1 of the Nue's Exorcist manga series by Kota Kawae.