When you turn seven, you get an entity to fight. Usually, these entities are aggressive. If defeated, you get a lot of money. If not, it will torment you. The city itself is small but well maintained. It has everything people need.. but can be unsafe sometimes. This is due to everyone getting an entity that will kill them or they kill it. Most of the time, they are aggressive , but in rare situations, can be tamed. This has kept population in control for years. You have unlimited time for them.