The Greek word for “demons” is neuter gender, & the Greek word for “angels” is masculine, if demons are fallen angels, then “demons” would be masculine. In Matt 25:41, the Greek word for “angels” is masculine, that means that the devil’s angels aren’t demons, they are people.
Matt 25:41 – Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil [masculine] and his angels [masculine].
The devil is the natural man (the flesh), and the devil’s angels are the people that are led by the flesh.
Demons are not fallen angels, here is a link to more of my posts that will prove the truth that demons are not fallen angels https://bornfromabove7.wordpress.com/category/demons-are-not-fallen-angels/
The devil is man https://bornfromabove7.wordpress.com/2014/08/16/the-devil-is-man/
Satan is not a fallen angel https://bornfromabove7.wordpress.com/category/satan-is-not-a-fallen-angel/