Envylia was once the brightest kingdom in Babel, with a dark past that has eventually caught up with it. Although full of legends and heroic deeds, the events of recent history have nonetheless resulted in the dismantling of the kingdom, and its heroes dissolved to different causes throughout the continent.
Below you can see the exact location of where Envylia once stood:
Envylia is one of the most prominent states in the lore, even after its dissolution, mostly due to its influential protagonists appearing in the very beginning of the Story mode and continuing ever since: Logi and Dias
For a complete lists of Units from Envylia, see here