Ruben is one of the simulators in West Korea. As a hunter of Kremlings, he is a trained professional in fucking people over. He is also easily angered and gets joy out of the pain of others. He's also kind of a glutton despite not packing any pounds and despite having barely any cooking skills.
Ruben was the 1st prime minister of West Korea until he was overthrown by Dolan Duck and was thought to have drowned. However, he applied as a simulator, disguised as a Kremling, and soon plans to carpet bomb West Korea in revenge.