The base is built upon several islands in Argus's harbor and is connected to the mainland by a large suspension bridge. Each island is identified by the letter A and a number.
Island A1 has a large rock spire, which has been dug into to house the base's Colossus. Island A2 is the storage and landing pad for the base's fleet of Airships. A third smaller island is also present, presumably this would be Island A3, its exact function is unclear, however.
Argus is part of Mistral, but the city is of great importance to Atlesian commerce. Thus, the Atlesians constructed a base in the harbor in order to protect the city from Grimm attacks. At some point, Caroline Cordovin came to be stationed at the base and was appointed as leader of the Atlesian presence.
Following the events of the 40th Vytal Festival, relations between Atlas and the rest of the world begin to deteriorate, and those between the Atlesian troops and the Argus populace are no exception. Caroline enforces James Ironwood's decision to close Atlas' borders and restrict transportation to the Kingdom.