Princes of the Apocalypse (TN 5e)
The Deep Gnomes (Svirfneblin) live in harmony with the rocks they carve and their natural environment.
The Deep Gnomes survive in domains that are populated by many implacable enemies. The two most dire among these are the Kuo-toa and the Dark Elves, who continually seek to drive these gnomes from territory they consider rightfully theirs.
The Deep Gnomes Clan known as the Crystalfist was no exception to this as the Kuo-toa attacked the clan and eliminated most of them.
Zook is the only survivor to his knowledge.