Zach really never amounted to much character-wise, his characterization summarized best as "directionless young adult". His kind are a strange outlier even within the messy Geoterra lore, dragon creatures that have no specific pre-evolved form and just sorta randomly evolve from whatever--I vaguely remember an attempt at designing one of these guys based on Geoterran Zebra girl Jenna at some point in the mid-2000s but I think that one was ruined when a pipe burst in the ceiling of my bedroom in 2008.