Roku is a location in Just Cause 4: Sakaku.
City blueprints reveal:
Roku was one of the more unfortunate "cities" in Sakaku. During World War II, it was one of the most heavily bombed cities in preparation of a Japanese amphibious landing, and then the Cold War saw little building reconstruction. Today, the city is nothing more but two huge unused skyscrapers amongst the ruins of decades past. The CLA have used these ruins to great advantage countering military offensives. Food and water are sufficient.