- Internal NPC ID: 38
The Demolitionist is an NPC vendor that will spawn once the following criteria have been met:
If the Demolitionist is killed, he will only respawn if the above conditions are met again. This means an explosive must be placed in the player's inventory again. Having explosives stored in chests or other containers will also fulfill the requirement.
|Hellfire Arrow||1||In Hardmode.|
|Land Mine||5||After defeating Plantera and a Pirate Invasion. |
Before defeating Plantera, at night.
|Explosive Powder||12||In Hardmode.|
|Stynger Bolt||10||Once Golem has been defeated.|
|Roman candle||5||During Christmas.|
|Dry Bomb||25||When the player has a Dry Bomb in their inventory.|
|Wet Bomb||25||When the player has a Wet Bomb in their inventory.|
|Lava Bomb||25||When the player has a Lava Bomb in their inventory.|
|Honey Bomb||25||When the player has a Honey Bomb in their inventory.|
|Any Pylon||10||When in a specific biome and is happy enough.|
Living preferences 
For more information, see NPC happiness.
- The Demolitionist will replace the Guide as the starting NPC in the secret seed "For The Worthy".
- The Demolitionist's weapons – Grenades – are surprisingly powerful, considering how early-on he may spawn in the game. Thus, he can be a great help during Blood Moons.
- Explosives, despite their name and crafting recipe, do not fulfill the demolitionist's requirement to move in.
The Demolitionist may have any of the following names:
In a Corrupt world:
In a Crimson world:
When Dryad is present:
When Nurse is present:
When Arms Dealer is present:
Only at night:
Only during a Blood Moon:
During a Party:
After defeating Tier 1 of the Old One's Army:
During a Windy Day:
When in a Graveyard:
Happiness quotes 
When far from home:
When in a sparse area:
When in the Caverns:
When in the Ocean:
When near the Tavernkeep:
When near the Princess:
When near the Mechanic:
When near the Goblin Tinkerer:
When near the Arms Dealer:
- The Demolitionist's appearance seems to be based on dwarves from many games, films, and works of literature. He is significantly shorter than other NPCs and has a beard. Furthermore, his mining helmet, lantern, and the fact that he sells explosives fits the trope of dwarves preferring underground environments. This is further proved by his Party-exclusive quote, one of his quotes while it is raining, his Happiness quote while in the Caverns, and his Bestiary entry. Several of his names are also references to dwarf characters in fiction:
- Beldin is from the five-book fantasy epic The Belgariad.
- Durim is a corruption of Durin, a dwarven king mentioned in the books of English writer J.R.R. Tolkien.
- Fikod and Urist are generic dwarven names from the indie video game Dwarf Fortress.
- Gimli is a reference to the epic high-fantasy novel The Lord of the Rings.
- Morthal is a name of a city surrounded by swamps in the action role-playing video game The Elder Scrolls V: Skyrim.
- Tordak (or Tordek) is a generic dwarf name in the fantasy tabletop role-playing game Dungeons & Dragons.
- The Demolitionist used to have the sprite for the Arms Dealer in the pre-release version.
- Though he is depicted in a painting called "American Explosive", the painting's name and appearance are a parody of the painting American Gothic, rather than an indication of his origin.
- In one of his quotes, he calls Ebonstone "ebonrock".
- The quote "Hey, could you sign this Griefing Waiver?" is referring to the term "griefing" used in video games, the act of ruining a player's game with actions such as destroying buildings.
- His Blood Moon quotes indirectly reference the fact that Clowns carry explosives.
- There appears to be a rivalry between the Demolitionist and the Arms Dealers, judging by lines of dialog from both the Demolitionist and the Arms Dealer that throw shade at one another, such as, "Don't bother with <Name of Arms Dealer>, I've got all you need right here."
- The Bestiary entry for the Demolitionist: "Tread carefully around this dwarf. The Demolitionist is an explosive fanatic and sells dangerous things that go 'Boom!'"
- Desktop 1.4.1: Changed his "Trying to get past that ebonrock, eh? Why not introduce it to one of these explosives!" quote to say "Ebonstone" or "Crimstone" (depending on the world's evil biome) instead of "ebonrock".
- Desktop 220.127.116.11: Buying a landmine requirement reduced from defeating Golem and at least one Pirate Invasion to defeating Plantera and at least one Pirate Invasion.
- Desktop 1.2: Now sells explosive powder and landmines.
- Desktop 1.1: Now has a random name given to him on spawn. His death will be reported with this name. Also, other NPCs will use it in their quotes.
- Desktop 1.0.3:
- Now triggered to arrive when the players have Sticky Bombs or Grenades in their inventory.
- Like other NPCs, can now be killed by enemies.
- Desktop-Release: Introduced.
- Console-Release: Introduced.
- Switch 1.0.711.6: Introduced.
- Mobile-Release: Introduced.
- 3DS-Release: Introduced.