Dark Gathering, Vol. 1 (manga)

An unwilling magnet for the supernatural and a ghost-hunting little girl join forces to capture Japan’s most terrifying and dangerous spirits. After a dangerous encounter with a malevolent spirit, Keitaro Gentoga wants nothing to do with the supernatural. Unfortunately for this reluctant ghost magnet, he’s stuck helping Yayoi Hozuki, a strange young girl who’s intent on capturing Japan’s most terrifying ghosts and ghouls. Keitaro is ready to stop living as a shut-in. He’s starting university. He’s reconnecting with his childhood friend. He’s taking a tutoring job. And he’s not messing around with ghosts anymore. At least that’s what he thinks, until he finds out the elementary schooler he’s tutoring is an occult-obsessed genius who’s hunting down dangerous ghosts and won’t stop until she’s found the one that took her mom.