 The dramatic end mentioned at the end of the novel, the fight between the ultimate Good and Evil reveals the deep spiritual nature which Conan Doyle had developed in his later years.Whereas the adventures of Sherlock Holmes show the keen analytical side of Sir Arthur, novels like "The Maracot Deep" show that he seriously took to spiritualism in his later years.It is not marked by any particular religion though there are strong Christian and Hellenistic undertones.