Emerald dragons were gem dragons who were inquisitive and often more knowledgeable than most sages.
Emerald dragons put a high emphasis on pride and honour. Those who do not follow these beliefs are looked down upon as cowards. They live solitary lives like all dragons, and refuse to join together, even if it means saving themselves. They see it as more honourable to die in battle alone then to join into a pack.
Emerald Dragon was an identity adopted by Jo Nah (Ultra Boy) while the Legionnaires were on the run, having been falsely implicated in collusion with the Khunds as a result of the machinations of Universo.