Your character has a “sixth sense” when it comes to the supernatural. Perhaps his hair stands on end, goose bumps race along his arms, or a shiver runs up his spine. Regardless of the manner, his body reacts to the presence of unseen forces. He can’t see or hear anything, and in fact he might not know at first what causes this reaction. It might be a response to a specific type of supernatural phenomenon such as ghosts or vampires, or it might be a general sense that something isn’t right. Overtime and with a little trial and error, he might be able to qualify what his body tries to tell him.