Caligastia is the titular Planetary Prince of Urantia until he was deposed at the time of Jesus.  Caligastia advocated the cause of Lucifer on Urantia.  He is now the deposed Planetary Prince of Urantia. He receives various names such as the devil, the evil one.  Abaddon was Caligastia's chief of staff. 
Caligastia was a secondary Lanonandek, number 9344.  He had been stationed on the advisory council of the Life Carriers on Jerusem.  Was elevated by Lucifer to a position on his personal staff.  He requested several times to be appointed as Planetary Prince but his requests were denied.  Eventually made Planetary Prince of Urantia.  He came 500,000 years after the appearance of the will on Urantia, time of the appearance of the colored races.  The commandments that he established in Dalamatia, his capital on Urantia, commanded obedience to his person.  Arranged for his work a corporeal staff of one hundred members.
He was extremely individualistic; restless; he resented the supervision; he had a tendency to disagree with the established order, and to join protest parties.  But he fell in love with himself.  Deliberate sin completely distorted his personality.  He was invisible to humans.  After his rebellion he was still an elevated Son, but a local universe misleader. 
Caligastia contested Moses' passage to the mansion worlds, and Moses had to wait for a special millennial or dispensational resurrection.  His power was restricted by the incarnation of Melchizedek and completely annulled by the incarnation of Michael.  Jesus warned the apostles that the enemy, that is, Caligastia, would seek to separate them.  Never able to oppress or coerce normal individuals against his will.  Caligastia never had any power to enter the minds of men unless they so desired. Human free will is supreme in moral matters.  Opposed Adam's mission even though he lacked most of his power.  Now he is stripped of all power to harm his subjects.  He was stripped of his authority during Michael's incarnation.  Since Pentecost he is servile to the Adjusters and the Spirit of Truth. 
His iniquity consisted in bypassing the temporary regulator of progressive human liberation.  Perverted all planetary schools.  He willfully betrayed the trust reposed in him.  Prostituted the divine talents for his own aggrandizement.  Tried to preempt a slow and sure way to accomplish the divine purpose. 
Held many conferences with Adam.  But he failed to involve Adam and Eve in the rebellion.  Serapatatia, one of Adam's lieutenants, was not aware of having been used by Caligastia for his own ends. 
Emmanuel instructed Michael to rule on the claims of the rebels as Caligastia, and to do so as a mortal and not as a heavenly being.  Caligastia was fully visible to Jesus on Mount Hermon, along with Satan.  Jesus defeated Caligastia on Mount Hermon and since then Jesus is the Planetary Prince of Urantia.  The rebels were silenced forever thanks to Jesus' life of selfless service.  Judas' betrayal pleased Caligastia.  Someone sat in Caligastia's place at the council of Planetary Princes that took place while Jesus was in the tomb.  Michael's last act on Urantia was to offer mercy to Caligastia, but Caligastia refused.  Caligastia is still free on Urantia. 
See also: UB 66.