Guide

The Guide is the first NPC that you encounter. His tips are mainly for new players to learn the basics of the game. He, unlike other NPCs, does not need a room to stay in at the beginning, but will move into the first one you build. Beyond providing tidbits of valuable information for new players, he is generally useless. The Guide is very very annoying after you get better and sometimes you will try to trap him. The Guide is immune to all types of damage except Lava, unlike other NPCs.

Guide's Tips
Poop all over their chest, they will love it and give you tons of money.
 * "You should stay indoors at night. It is very dangerous to be wandering around in the dark."
 * "Underground are Crystal Hearts that can be used to increase you max life. You will need a hammer to obtain them."
 * "If you gather 10 Fallen Stars, they can be combined to create an item that will increase you magic capacity."
 * "Stars fall all over the world at night. They can be used for all sorts of useful things. If you see one, be sure to grab it because they disappear after sunrise."
 * "For a nurse to move in, you might want to increase your maximum life."
 * "If you had a gun, I bet an arms dealer might show up to sell you some ammo!"
 * "You should prove yourself by defeating a strong monster. That will get you the attention of a dryad."
 * "You can make a Grappling Hook from a hook and 3 chains. Skeletons found deep underground usually carry hooks, and chains can be made from iron bars."
 * "If you see a pot, be sure to smash it open. They contain all sorts of useful supplies."
 * "There is treasure hidden all over the world. Some amazing things can be found deep underground!"
 * "Smashing a shadow orb will cause a meteor to fall out of the sky. Shadow orbs can usually be found in the chasms around corrupt areas."
 * "You can tell a Blood Moon is out when the sky turns red. There is something about it that causes monsters to swarm."
 * "Two people will not live in the same home. Also, if their home is destroyed, they will look for a new place to live."
 * "If you combine 10 lenses at a Demon Altar, you might be able to find a way to summon a powerful monster. You may want to wait until night before using it, though."