Maybe the demons are the aliens. As a Christian one would call them demons, a non religious person may classify them as aliens.
As Michael Heiser would say, when some people perceive that aliens are demons, they are confusing fallen angels with demons. Demons, according to Heiser, are the berserk spirits of the Nephilim, not fallen angels (who are the parents of the Nephilim – See Genesis 6 and Heiser's Unseen Realm).
“As a Christian one would call them demons, a non religious person may classify them as aliens.”
A La “Childhood’s End”.