Captain Tost served as an officer within the InterGalactic Banking Clan's Collections and Security Division. He commanded the Iotran Guard, with his duty being the safeguarding of the Banking Clan's collection of vault worlds distributed across various planetary systems; he was supported in this role by IG-100 MagnaGuards. During the Clone Wars, which spanned from 22 BBY to 19 BBY, Tost and the Banking Clan aligned themselves with the Confederacy of Independent Systems against the Galactic Republic, integrating both himself and the Iotran Guard into the Separatist Droid Army.
Tost's initial appearance in current Star Wars canon was in Rise of the Separatists, a 2019 addition to the Star Wars Roleplaying game line by Fantasy Flight Games. Within the Star Wars Legends timeline, the character Riklon Tost was first conceived for Geonosis and the Outer Rim Worlds, a 2004 resource published by Wizards of the Coast for their Star Wars Roleplaying Game.