NPCs

NPCs are non-player characters. They will move into vacant houses if certain conditions are met (except for the Old Man). For an NPC to spawn, you will need to build a complete house.

Each NPC also has an additional requirement. For example, you will need to collect 50 Silver Coins for a Merchant to appear. See individual NPC pages for their requirements.

The Guide will spawn upon creating a world, but will also move into the first house you build. If a house is destroyed in any way, the NPC will move out, but will return once the house is restored or a new one is built elsewhere.

All NPCs are vendors, except the Guide and the Old Man. The Nurse doesn't sell items, but provides healing in exchange for money.

All NPCs have a set amount of health and will take damage from enemies, except the Guide. If an NPC dies but the house remains, it will respawn after a short time. NPCs also have regenerating health, which ensures you don't need to manually heal them once they've taken damage and the threat is gone.

Requirements
See: House

The general requirements for an NPC to spawn is to have a closed room with at least 1 door. The room should be walled completely. The room can not have empty spaces for a window, it must be filled in with glass or no one will move in. The room needs to be at least 6 blocks high (the space inside after the floor and roof is 4 blocks high), and fit the required additions inside it. The room needs to have at least one light source. Finally the room needs to have some Furniture: A Chair and a Table is enough.