Demolitionist

The Demolitionist is an NPC vendor that will spawn once the following criteria have been met:
 * There is an empty house.
 * You have one of the Explosive Consumables in your inventory.

Once the Demolitionist has moved into a house, he will sell the following:

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. He and the Arms Dealer also seem to have a rivalry.