"Legions" has a demonic connotation in the bible.
FALLEN ANGELS are demons.
Mark Chapter 5:1-9
Jesus Heals a Man with a Demon
They came to the other side of the sea, to the country of the Gerasenes.
And when Jesus had stepped out of the boat, immediately there met him out of the tombs a man with an unclean spirit. He lived among the tombs. And no one could bind him anymore, not even with a chain, for he had often been bound with shackles and chains, but he wrenched the chains apart, and he broke the shackles in pieces. No one had the strength to subdue him. Night and day among the tombs and on the mountains he was always crying out and cutting himself with stones. And when he saw Jesus from afar, he ran and fell down before him. And crying out with a loud voice, he said, “What have you to do with me, Jesus, Son of the Most High God? I adjure you by God, do not torment me.”
For He was saying to him, “Come out of the man, you unclean spirit!”
And Jesus asked him, “What is your name?”
He replied,“My name is Legion, for we are many.”