Biome
Underground
Underground is a Terraria biome. 14 NPCs spawn here: 
Clothier, 
Demolitionist, 
Digger and 11 more.
What spawns here
Any time 14
Town NPC happiness
Town NPCs rate the biome where you shop, here the Underground.
- Likes: Clothier, Demolitionist,
Goblin Tinkerer - Dislikes:
Golfer, 
Mechanic, 
Party Girl, 
Pirate