The enemy includes a whole multitude of fallen angels and demons.... Who... What... When... Where... How... Why... I seek these answers to identify "the enemy"
Main prayer Jesus gave us - "Our Father in Heaven" (Matthew 6:9-13) - ends with:
"And lead us not into temptation, but deliver us from the evil one."
Jesus told us to regularly pray to God to deliver us from the evil one. That means that evil one is attacking us regularly. That's the answer to your questions "Who", "When", "Where", "What".
It's confirmed by 1 Peter 5:8-9: "Be alert and of sober mind. Your enemy the devil prowls around like a roaring lion looking for someone to devour. Resist him, standing firm in the faith, because you know that the family of believers throughout the world is undergoing the same kind of sufferings."
It leaves "How" and "Why".
"Why" is because we are Adam's and Eve's descendants - "And I will put enmity between you (
serpent) and the woman, and between your offspring and hers" (Genesis 3:15) - plus, we are still in our mortal sinful bodies, living on perishing Earth (not resurrected yet).
"How" is probably only by oppresion for believers/elect/born-again, since Jesus told us: "I give them (
my sheep) eternal life, and
they shall never perish;
no one will snatch them out of my hand. My Father, who has given them to me, is greater than all;
no one can snatch them out of my Father’s hand. I and the Father are one." (John 10:28-30)
So, the evil one (and his minions) is doing his part within God's plan, while believers are learning and growing through it, but not in danger to perish.
I would suggest two things to you. First, pray more to God to deliver you from the evil one. Second, command evil one in Jesus name to disappear, vanish, drop into the pit everytime you feel or think he's there (Matthew 10:8).