Who is Dr. Ransom, The Fisher King, the Pendragon, the Director from That Hideous Strength and what is their importance?

Dr. Ransom is one of the few characters common throughout this novel and the previous two novels in the trilogy. His history is briefly recapitulated in this novel. It seems that he has disappeared twice in his life, and one of these times he came back to say that he had been kidnapped and taken to the planet Mars. The second time he went to Venus, or Perelandra. While he was on Mars, he met heavenly beings called eldils, as well as beings called Oyeresu. He communicates with these groups of beings in this novel, and it is them that help save humanity, by communicating with Dr. Ransom.