Black City's population changes with time. The appearance of Black City alters with the number of varying Trainers residing there. When the player enters the city for the very first time, the total number of varying Trainers is determined by the number of days it took the player to reach Black City, decreasing as time goes by. The number of overall residents can vary between 12 (minimum occupancy) and 45 (maximum occupancy), 12 of them being Trainers at the maximum (including the two trainers inside the marketplace, both of whom can only be battled once). In addition to the visual changes, the city's market will sell items to the player at inflated prices, dependent on which varying Trainers are in the city. The items are rare, with most being either evolutionary stones or valuable items.