Fridge Horror: There are at least a couple of passing references to "Ragnarok" in the series, including "Ragnarok Canyon" and "Ragnarok Cheese."
Fridge Logic: The four main Dragon characters are implied to have parents, who, if they show up, are shown to be much larger than them, and yet, Quetzel, a dragon much older than the four, is only about two feet taller than Ord. Ummmm....
Miniature senior citizen?
Or it could be part of Quetzal's Stealth Mentor gig. He probably intentionally represents himself as smaller than he is in order to better relate to the children as a guide so they don't treat him as a parent.