The boogerman.
I truly hope you are not insulted, OWK, that Kreeft didn't mention atheists too by name (or did I miss that) as NOT being our enemy either. Sorry.
The majority of healings Jesus did were delivering people from demons. Demons are real. Satan is real. God explains in great detail the evil that surrounds mankind.
Do you dine with him often? Or just when the mood strikes him?
Deception is the enemy's tool