The Doctrine of Apocatastasis holds that in the end of time, all creatures will be reconciled to God, including Judas Iscariot, Satan, and the demon hordes. Its most famous progenitor was Origen, who believed after the final reconciliation, there could be another great fall, beginning the process of salvation history all over again. As a result of this theology, Origen was condemned as a heretic by the Fifth Ecumenical Council (II Constantinople) in 553.
Positive article by Metropolitan Kallistos Ware in the new "Complete Works, Vol. 1"
Other works: The inner kingdom by Kallistos, Bishop of Diokleia Type: Book; English Publisher: Crestwood, NY : St. Vladimir's Seminary Press, 2001.