Sort of like a dark[sic] serpent, but fire[sic] elemental...In-game description
The Zelth is the Stage 2 balanced form of the Umbral group.
Zelths cannot be found in the wild. They are not used by any enemy signers, except for those participating in the Random Tournament.
A Zelth can be evolved from a Zeode. In the alpha version it cannot evolve again.