Elwin Ransom
Elwin Ransom may be based on C. S. Lewis' friend J. R. R. Tolkien ("Elwin" means "Elf friend" in Anglo-Saxon), though he seems to have autobiographical elements. In "That Hideous Strength" Ransom, with his royal charisma and matter-of-fact breezy acceptance of the supernatural, appears less like Tolkien than like Charles Williams (or some of the heroes in Williams' books).
Hugo Dyson
Henry Victor Dyson Dyson (7 April 1896 – 6 June 1975), generally known as Hugo Dyson and who signed his writings H. V. D. Dyson, was an English academic and a member of the Inklings literary group. He was a committed Christian, and together with J. R. R. Tolkien, he helped persuade C. S. Lewis to convert to Christianity.