Hand of the Automaton
The Silent Sea
The idea here is that a sea was drained and evaporated as part of the war, leaving behind the sea floor covered in shipwrecks, crevices, all that kind of stuff, as well as mutated sea-life.
This would be a location not unlike a desert in many games, but with distinct touches to make it clear that this was once all underwater.
As far as the backstory, I was thinking that he wizard drained the sea to create massive storms and hurricanes which he used as a weapon against the empire’s inland cities, causing massive devastation.