Nigon is the second underground race.

Maybe then: "The Exiled", "The Caves", or "The Underlords". Their name should be associated with their history. Something like: they lived underground, didn't bother anyone, dug tunnels, searched for something valuable, and then they dug up someone and things went south. He really gave them a hard time. So they crawled out from under the ground, and there was such a mess going on. And they got caught up in the general chaos. Does that work?