The lost clan of Gnomes had lived in another underground city and their leader had undertaken some grisly experiments. The other Gnomes got wind of it and marched on the city to take control and arrest the renegade leader. He skipped town with his followers, but left behind a little surprise for the army. As the troops entered the city a massive explosion rocked The Beneath that some say could be felt all the way up to the surface world. Surviving Gnomes were blinded and sickened.
Of course, no one knows what happened to the ex-leader, but descendants of his followers are still around and, although regarded badly by other Gnomes, are allowed into the capital city to conduct business.
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