Arko was a Waska. He was one of two Waskas, besides Forno, who accompanied Bernice Summerfield and Shell on their expedition to Venedel. Whilst there he was attacked by Renad and Maddaska for being a "beast". When investigating the temple he found structural changes to the building that he thought were strange. He was the first to think that Starl Stanmore liked Benny. (PROSE: The Gods of the Underworld)
Arko, along with the rest of his team members, attended Bernice's baby naming ceremony for Peter Guy Summerfield. (PROSE: The Glass Prison)