Lucifer is the protagonist of this track. Geezer Butler, who wrote this lyrics, explained in the 1992 documentary “The Black Sabbath Story: Volume One”, “The song was about the devil falling in love and totally changing, becoming a good person.”
I used to jam Sabbath while cruising in my Burt Reynolds Trans Am with the T-tops off and the Sun shining.
(Ironman, Fairies Wear Boots, NIB, Sweet Leaf, etc.)
Good times...