As for the killer himself, John Doe also chooses to don more practical clothing. He wears a long, dark jacket with a wide brimmed hat that conceals his face. This implies that, like Somerset, he is a practical and methodical man. Apart from practicality, this creates a sense of mystery in the character. At this point, nobody has any idea what the killer looks like, his face is never seen. The fact that he is wearing all black also shows that this is a very dark and mysterious character; you can tell from the very first glance that he is the ‘bad guy’ of the film.