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, in some cases, sell unique items that are otherwise unavailable. The Demolitionist is a unique NPC who sells explosives and related items, making him valuable for mining and combat scenarios. To maximize his happiness, you need to place him in the right biome and pair him with the right neighbors.

The Demolitionist prefers the Underground biome, which includes areas like the Cavern layer or any underground biome such as the Underground Desert or Underground Snow. He dislikes the Ocean biome and the surface biomes like the Forest. Placing him in his preferred biome will increase his happiness. Additionally, the Demolitionist has specific preferences for neighbors. He likes the Tavernkeep and the Mechanic, but he dislikes the Arms Dealer and the Goblin Tinkerer. Pairing him with the Tavernkeep or Mechanic will further boost his happiness, while placing him near the Arms Dealer or Goblin Tinkerer will decrease it.

To start, you need to create suitable housing for the Demolitionist in the Underground biome. This involves digging down to the Cavern layer and building a house using blocks, walls, a table, a chair, and a light source. Make sure the house is valid by checking the housing menu. Once the house is ready, assign the Demolitionist to it. Next, place the Tavernkeep or Mechanic in a nearby house within the same biome. This will ensure that the Demolitionist has a preferred neighbor, increasing his happiness.

One common mistake is placing the Demolitionist in the wrong biome or pairing him with disliked neighbors. For example, placing him in the Ocean biome or near the Arms Dealer will make him unhappy, leading to higher prices and no unique items. Another mistake is overcrowding the area with too many NPCs, which can reduce happiness. To avoid this, keep the number of NPCs in the area to a minimum, focusing only on those that the Demolitionist likes.

Advanced techniques involve optimizing the placement of NPCs to maximize happiness across multiple characters. For example, you can create a small underground town with the Demolitionist, Tavernkeep, and Mechanic, ensuring all three are happy. This setup not only benefits the Demolitionist but also the other NPCs, as they will also receive happiness bonuses from being near preferred neighbors. Additionally, you can use pylons to create a network of teleportation points, making it easier to travel between different biomes and NPC setups.

Resource requirements for this setup are minimal. You need basic building materials like wood, stone, or any other block type to construct the houses. You also need to ensure you have enough light sources, such as torches or lanterns, to make the houses valid. If you are playing in Hardmode, you might want to consider using stronger materials like stone bricks or dungeon bricks to protect the houses from enemies.

In terms of class and equipment considerations, the Demolitionist is particularly useful for players who focus on explosives and mining. If you are playing as a melee or ranged class, you might not interact with him as much, but his discounts on explosives can still be beneficial for clearing large areas or mining efficiently. For players who use explosives in combat, such as those using the Demolitionist's grenades or bombs, keeping him happy is crucial for maintaining a steady supply of affordable explosives.

Specific examples of scenarios where the Demolitionist's happiness is important include large-scale mining operations, where you need a lot of explosives to clear out areas quickly. In these cases, having a happy Demolitionist will save you a significant amount of money. Another scenario is during events like the Goblin Army or Pirate Invasion, where explosives can be used to deal massive damage to groups of enemies. A happy Demolitionist will provide you with cheaper explosives, making these events easier to handle.

In conclusion, making the Demolitionist happy in Terraria involves placing him in the Underground biome and pairing him with the Tavernkeep or Mechanic. Avoid placing him in disliked biomes or near disliked neighbors, and ensure his housing is valid and not overcrowded. By following these steps, you can maximize his happiness, leading to discounts on his items and access to unique explosives. This setup not only benefits the Demolitionist but also enhances your overall gameplay experience, especially if you rely on explosives for mining or combat.