Goblin Tinkerer

A Goblin Army has to be beaten first. After that, a tied-up goblin starts turning up at random in the Cavern layer while you move around down there, and interacting with him cuts the rope. He walks off and claims any empty house you have waiting. Kill him by mistake, or lose the settled vendor later, and another spawn comes around eventually so long as a room is free.

He spawns near you and vanishes if you wander too far, so combing the map cave by cave achieves nothing. Keep moving through open underground space and the rolls come to you. The Dungeon works well because it is big and easy to run, and bound NPCs turn up in the Jungle Temple too. A Hunter Potion lights him up through walls and the Lifeform Analyzer calls him out by name.

On Remix and Zenith worlds the Cavern layer sits near the top of the underground instead of deep down, so look far shallower than instinct says.

Talking to him lets you reroll the modifier on any weapon or accessory. It is a slot machine with no stop button: each pull can land better or worse than what you had, and the only way to keep a good roll is to walk away. Every attempt costs a share of the item's current value, and since the modifier itself changes that value, an item that just rolled something expensive costs more to reroll again. Budget for a long session on anything endgame.

Newer versions play a small effect and briefly lock the button when you land the top modifier, which kills the classic mistake of mashing straight past the roll you wanted.

Reforge cost scales with his happiness, so where he lives is worth real money over a playthrough. He wants to be underground, in the Cavern or the Underworld, with the Mechanic and the Dye Trader as neighbors. Build that once and it pays for itself. A Discount Card or Greedy Ring shaves it further.

For anything craftable there is a free route: break it down in Shimmer and craft it again, which rerolls the modifier at no cost at all. That does nothing for dropped or purchased gear, which is exactly where his prices bite hardest.

The Tinkerer's Workshop is the single purchase that matters and it should happen on the first visit. Accessory combining is gated behind it, and half the slots you want later are combined items rather than drops.

Rocket Boots are in the same category. They are not a piece of kit you keep as is, they are the base of the entire movement accessory chain. The Toolbelt extends your block reach and is the kind of quality of life buy you forget you made because you never notice it again.

The Ruler and the Rubblemaker are builder tools rather than combat gear, but the Ruler is cheap enough that there is no reason to skip it if you place blocks at all. Spiky Balls are the throwaway line: they hold a doorway during an early invasion and stop mattering shortly after. The Grappling Hook is only relevant if you never got around to making one from gems.

Enemies near town get pelted with spiky balls, and his damage rises as you clear bosses. He is the only goblin that uses them as a weapon, and the only one who leaves none behind when he dies.

The name pool is mostly goblin-sounding invention with a couple of jokes hidden in it. Dalek points at the exterminating machines from a British science fiction show, and Gnudar looks like a nod to an alien antagonist in an animated sci-fi comedy.

His line about putting rockets in your running boots is both a meme reference and an actual hint, since that combination is one of the first things the Workshop lets you build. He and the Mechanic have a running thing for each other that shows up in their quotes, in the emotes they trade across town, and again in the credits.