After the apocalypse, mankind basically managed to restore normal life, but some heavily destroyed cities simply decided not to restore. It's too expensive, cheaper to build a brand new one elsewhere. Several cities were razed to the ground, but they still decided to leave a couple to turn into an arena for training fighters. Among the ruins there are a lot of weapons and ammunition, so initially all who wish to fight go there with only one combat dagger. If you want to survive, look for a weapon and use it to destroy your rivals and become a winner in the Shooter Arena.
