When asked why he portrayed Satan—an androgynous, almost beautiful being played by Rosalinda Celentano—the way he did, Gibson replied: "I believe the Devil is real, but I don't believe he shows up too often with horns and smoke and a forked tail. The devil is smarter than that. Evil is alluring, attractive. It looks almost normal, almost good—but not quite.
"That's what I tried to do with the Devil in the film. The actor's face is symmetric, beautiful in a certain sense, but not completely. For example, we shaved her eyebrows. Then we shot her almost in slow motion so you don't see her blink—that's not normal. We dubbed in a man's voice in Gethsemane even though the actor is a woman … That's what evil is about, taking something that's good and twisting it a little bit."
But what about the ugly baby?
"Again," said Gibson, "it's evil distorting what's good. What is more tender and beautiful than a mother and a child? So the Devil takes that and distorts it just a little bit. Instead of a normal mother and child you have an androgynous figure holding a 40-year-old 'baby' with hair on his back. It is weird, it is shocking, it's almost too much—just like turning Jesus over to continue scourging him on his chest is shocking and almost too much, which is the exact moment when this appearance of the Devil and the baby takes place."