Honbul

The Exorcism Agency is a state-run secret organization whose mission is to protect humans from demonic possession. Taehee Yoon, an exorcist from the Execution Department, is looking for a "genius" who can see and hear ghosts to be his new subordinate. While operating undercover at a high school he meets a mysterious boy...
"By the way, how old are you, buddy?"

(Source: Manta)