You have a gun, which can be used to defend yourself from other people and the monsters as well. In most cases it won't STOP the monster, but it may slow them down. Only firearms hurt/slow monsters with any reliability.
Firearm is a perk. It can be purchased for 10 points in character creation, or may be available free with faction membership in some stories.
This perk is or has been available in the following stories • Slasher •