Cuidad de Arias was one of a number of cities on Verge, a UEG colony conquered by the Covenant. A Beacon was set up near the city, and it provided Team Black with cover as they inserted into the area to try and destroy it. Hopalong made contact with the Spartans in a structure in the city, enlisting their aid in a massive escape attempt of a Yanme'e colony. After the Yanme'e inmates turned on the Spartans, they used the still-functioning Arias transit system to escape to a Pelican extraction.