Originally Posted by
Hitei
Kezan is an island that has a port city on it, Bilgewater Port, controlled by the Bilgewater Cartel. The survivors of the Port, who left the island when it erupted, are who the Horde Goblins are.
Undermine is a much, much larger city that is deep under Kezan, and it is the Goblin home city. It's run by multiple cartels, including the Bilgewater, but also the Steamwheedle, the Venture Company, etc. It is inherently neutral, because it's a huge trade hub and the cartels and factions of Goblins that live there have all sorts of associations.