Seven School Mysteries part 2

The group from the occult club decided to make preparations for their investigation for the next day. As the group left the clubroom Loki once again felt that mysterious presence as if it was looking right at him, but before he could do anything the presence disappeared. 

Loki closed his eyes and expanded the range of his mana sensing but he could not find a single trace of the other party. 

'Is there someone in this world who can erase their presence better than me?'