How do I make the Demolitionist NPC happy in Terraria?

To make the Demolitionist NPC happy in Terraria, you need to understand the NPC happiness system, which was introduced in the 1.4 update. This system allows NPCs to have preferences for specific biomes and neighbors, which directly affects their happiness. A happy NPC will offer discounts on their items and may even sell unique items that are otherwise unavailable. For the Demolitionist, his happiness is influenced by the biome he lives in and the NPCs he is housed near.

The Demolitionist prefers to live in the Underground or Cavern biomes. These biomes are located below the surface layer of the world, and you can identify them by the background walls and the type of blocks present. The Underground biome starts just below the surface layer and extends down to the Cavern layer, which is deeper and has a darker background. To make the Demolitionist happy, you should build his house in one of these biomes. You can check the biome by opening the map and looking at the background or by using a Depth Meter, which tells you the depth you are at.

In addition to the biome preference, the Demolitionist also has specific neighbor preferences. He likes to be near the Tavernkeep and the Mechanic. The Tavernkeep is an NPC who sells items related to the Old One's Army event, and the Mechanic sells wiring and mechanical items. Placing the Demolitionist's house near these NPCs will increase his happiness. However, he dislikes being near the Arms Dealer and the Nurse. The Arms Dealer sells guns and ammunition, and the Nurse provides healing services. If the Demolitionist is housed near these NPCs, his happiness will decrease.

To set up the Demolitionist's house, you will need to gather materials for building. You will need blocks, walls, a table, a chair, and a light source. You can use any type of block and wall, but it is a good idea to use materials that match the biome. For example, in the Underground biome, you can use stone bricks or gray bricks. In the Cavern biome, you can use mudstone or smooth marble. Make sure the house is at least 6 blocks wide and 10 blocks tall, with a door and a light source like a torch or a lantern.

Once the house is built, you can assign the Demolitionist to it by talking to him and selecting the "Housing" option. If the house is suitable, he will move in. You can then check his happiness by talking to him and selecting the "Happiness" option. If he is happy, he will mention that he likes the biome and his neighbors. If he is unhappy, he will complain about the biome or his neighbors, and you will need to adjust his housing accordingly.

One common mistake is placing the Demolitionist in the wrong biome or near NPCs he dislikes. This will make him unhappy and reduce the discounts he offers. Another mistake is not providing enough space in his house. The house must meet the minimum size requirements, or the Demolitionist will not move in. Additionally, make sure the house is fully enclosed with walls and a roof, or it will not be considered valid housing.

Advanced techniques for optimizing the Demolitionist's happiness include creating a dedicated NPC town in the Underground or Cavern biome. You can build multiple houses in this biome and assign the Demolitionist, Tavernkeep, and Mechanic to live near each other. This will maximize their happiness and provide you with discounts on their items. You can also use teleporters or minecart tracks to quickly travel between the surface and the Underground biome, making it easier to access the Demolitionist's shop.

Resource requirements for building the Demolitionist's house include blocks, walls, and furniture. You can gather these materials by mining or crafting. For example, you can craft stone bricks by smelting stone at a furnace. You can also craft furniture like tables and chairs using wood at a workbench. Make sure to gather enough materials before starting the construction, as you may need to build multiple houses if you are creating an NPC town.

Class and equipment considerations are not directly related to the Demolitionist's happiness, but having the right tools can make the process easier. For example, a pickaxe with high mining speed will help you gather materials faster. A grappling hook or wings can help you navigate the Underground biome more easily. If you are playing as a ranged class, you may want to purchase explosives from the Demolitionist, which can be useful for mining or combat.

In summary, to make the Demolitionist happy in Terraria, you need to build his house in the Underground or Cavern biome and place him near the Tavernkeep and Mechanic. Avoid placing him near the Arms Dealer and Nurse, as this will decrease his happiness. Gather the necessary materials for building, and make sure the house meets the size requirements. Check his happiness by talking to him, and adjust his housing if necessary. By following these steps, you can maximize the Demolitionist's happiness and take advantage of the discounts and unique items he offers.