Science fiction combines imagination with ultimate questions. Therefore, it is appropriate that recently we compared ERB's John Carter with Robert Heinlein's Lazarus Long and Poul Anderson's Hanno and also discussed the significance of Jesus of Nazareth. All of these characters defy death in different ways. Carter died on Earth but lives on Mars and saved the lives of nearly everyone on Mars.
Jesus is, of course, controversial. I categorize him as part historical figure and part "higher fiction," to quote Alan Moore's description of religions. Jesus is relevant here not only because fictional characters include Christians but also because he is the White Christ in Anderson's Norse-based fantasies and plays an active role in CS Lewis' fantasy and sf. He signifies something endless.