Joe Miller is a former Pittsburgh detective and the current Occupant. After receiving The Key he found himself in the middle of the war for the Objects. When his daughter was reset in the Room, he stopped at nothing to get her back, going so far as to shoot Eddie McCleister in the Room and become the Occupant.
The Key is an Object with the ability to open a door to the Room. It is one of the most sought after Objects out there, fetching a price of $2 million when sold. The Key landed in the hands of Joe Miller who, after losing his daughter in a reset, used the Key to travel around, seeking a way to gain his daughter back.