Loker is a mysterious figure in a green cloak who you first meet at the Aurora city Shrine. He is sarcastic and a bit jaded by life, but he helps you get to each ruins safely when you explore. It appears that he works as an emissary between Selan the Shrine Master and the various bosses in the ruins.
Even though he handles most of the artifacts, Loker is a bit put off by how Selan always makes him do the grunt work, but seems to take the credit. However, he stays because he has a crush on Colon.
When seen at the Shrine, his name is spelled "Roker" instead of "Loker," but in Japanese, his name is Rōkā in both locations.