Brackett and Lucas came up with various ideas for subplots, including a love triangle (Lucas compared Han to Rhett Butler, Leia to Scarlett O'Hara, and Luke to Ashley Wilkes in "Gone with the Wind"), the reintroduction of Obi-Wan as a ghost, an arctic world inspired by "Flash Gordon" (1939–1940) and "The Thing from Another World" (1951), further development of the Force, and the new Jedi master being an elderly, froglike alien. They also conceived new aliens, planets, and the notion that the Emperor, not Darth Vader, is the true villain.