This group of people that had arrived were actually members of a fighting club before the apocalypse descended. And when it arrived, it was just during the time that they were having a tournament.
At that time, they banded together and decided that they were going to form a base of their own. So, during the time that the monsters attacked, they hardly left the area, and looked for a safe place to hide.
It was only after they had killed one monster that they suddenly realized that, by killing the monsters, they were getting stronger. So, they no longer hesitated and neither did the they continue hiding.
As such, they set out and began hunting the monsters, getting stronger and stronger. After a while, they were given the option to select a profession that they liked.
