Argents are the real money currency of Skyforge, They can be obtained in exchange for Credits or with real money (Dollars, Euros, Rubles). Argents can also be exchanged for Credits. Argents can also be obtained by selling Medium Replicator Containers received during story missions.
Argents can also be used to activate Premium Mode, which allows you to obtain Sparks of Evolution and 50% extra Sparks and Credits, which stacks with the Replicators to give a 100% bonus Sparks. Note that you need at least 2,000 Argents to activate Premium Mode for a minimum of 3 days and a maximum of 45,000 to activate it for 180 days.