Not all Christians believe that demons exist in the literal sense.
The demon was existing forward, while Chronos existed backward.
Joe eventually agrees to help, but is still not certain that the demon exists and is worried when Duncan won't take back his sword.
Early investigators eventually concluded that such demons did not really exist, even though they often left footprints behind and caused physical damage.
Most people didn't believe that demons, ghosts and curses existed.
As the target audience is young, the story takes the liberty to draw a fantasy world, in which wizards, demons and other strange creatures exist.
The Buffyverse is a world where Vampires and demons exist.
Fear runs rampant throughout Tokyo with the revelation that demons in fact exist amongst us.
"From my theological beliefs, I accept that demons exist," he replied.
A similar demon under another form of the name exists in Gunni belief.