It's normal for youngsters to have imaginary friends, but what about imaginary enemies like demons?

The Bible says that even though God is invisible, He sees everything and has myriads of angels roaming the earth, reporting what we do back to Him but it also says that the invisible Satan also has demons watching all of us too, trying to tempt us to do wrong.
https://wol.jw.org/en/wol/pc/r1/lp-e/1200026366/187/0
https://wol.jw.org/en/wol/d/r1/lp-e/102011131?q=is+jehovah+omnipresent&p=par

jw.org.Jehovah's WitnessesKim Mikey