lfg

You can only have one Pylon of a given biome type placed at a time (so you can not have, for example, an Ocean Pylon at both Oceans)

Pylons must be placed in their aligned biome in order to function (you can place them anywhere else, but they will not work!)

Pylons must also have two nearby (and living) NPCs in order to function - again, the idea here is to reward building those bases/towns! :)

Pylons cannot be used during Boss Battles or Invasion Events!

NPCs are happier when you locate them in biomes that they prefer
NPCs are happier when they like their neighbors
NPCs are happier when they are not overcrowded with other NPCs

NPC Shop prices will adjust based upon how happy each NPC is at the time
If you make an NPC happy enough, you will gain access to a Pylon for that Biome (more on this below!)