Complex sentence: In "Garden of Souls", Sapien is contacted by Panya, an ageless mummy trapped by the Oannes Society, Sapien's compatriots from his former life as Langdon Caul, who are sequestered away on a hidden island in Indonesia.
Split into simpler sentences: In "Garden of Souls", Sapien is contacted by Panya, an ageless mummy trapped by the Oannes Club. The Club proves to be made up of Sapien's compatriots from his former life as Langdon Caul, who are sequestered away on a hidden island in Indonesia.