Arcius has conquered most of the planets in the universe except for one, Earth. His goal is to set up a beacon in Gravity Falls, Oregon so when the time comes, the extraterrestrial armada near Earth's orbit will know it's time for the invasion.
Arcius is brutal and knowledgable. He shows off his strength by using the bones of his dead enemies as ornaments for his suit. His 'rival' resides in Gravity Falls, Oregon.