All the inhabited planets in the System of Satania had a Planet Prince. This Planet Prince was located in Mesopotamia, but he wasn’t visible to humans. His job was to negotiate relationships among the six races and the various tribes. He employed visible workers to train the tribes in the domestic arts and agriculture. A Planet Prince appears on a planet when evolution has achieved an erect homo sapien, an intelligent species. Another milestone in a planet’s history is the arrival of Adam and Eve, sent from the System headquarters, Jerusem, to uplift the races. They produced children, who then mated with superior elements of the other races. But they were not successful on Urantia. They had to default because they angered the tribes. They couldn’t go back to Jerusem, so they had to become mortal and live and die, sharing the mortal fate. So Earth doesn’t have its share of the violet race mixed among the other races. The violet race, Adam’s race, was supposed to lift the other races to a more civilized and superior level. That didn’t happen.
Our Planet Prince, Caligastia, sided with Lucifer in his rebellion, along with Satan and various angels. Lucifer was a brilliant Lanonondek Son, a group of beings created by the God Michael (Jesus) to be System Sovereigns and Planet Princes. Lucifer was a long-time System Sovereign before he rebelled. Because he had never been out of the universe of Nebadon, he had never been to Paradise and didn’t believe the Universal Father existed. He thought that Michael had invented the Father for nefarious reasons. Lucifer also believed that self-government should start at the System Level, so he installed a legislature on Jerusem. God Michael didn’t intervene in any of this, giving Lucifer plenty of rope to hang himself.
Gabriel, Michael’s chief executive, started a war of words with Lucifer. This lasted until the Ancients of Days, the 3 rulers of the superuniverse of Orvonton arrested Lucifer and Satan and put them on trial. They were found guilty of various crimes and sentenced to death. But they were given a choice. They could be executed by the court or they could annihilate themselves. They chose to self-annihilate. This last bit of information does not come from the Book. It comes from a download given to a channel, and, as such, it can be thought of as an interesting tidbit but not much more. According to the Urantia Book, Lucifer and Satan are cooling their heels in the Father’s prison planet on a satellite of Jerusem.