Dark Gaia

Elder is a wise man who lives on Crysta, the underground village.

Elder is just using Ark, and he actually is Dark Gaia, and he create Crysta, copying the village of the outside world, including the people, like Ark.

Source: Terranigma/Tenchi Souzou Manga http://www.mangareader.net/1368/tenchi-souzou.html And the original game for snes (same story and same creator of the manga)