There is also demonic influence and demonic possession of the soul or thinking faculties of man. For the beleiver in Christ, we are sealed with His ministry and indwelt by Him.
This is not yet the case for the unbeliever.
Considering how many different people there are in our own understanding and how many different species in the zoo, I sometimes wonder how many times we might be exposed to different demons and simply associate their presence with a different human perspective, when in reality we might actually encounter something far more sinister which we have been given ample warning to discern.
On the other hand, when you do bump into one and it is obvious, there isn't much room for doubt.
I've known people who, to the outward appearance, looked to be the most upstanding, finest pillars of the community imaginable yet I felt an icy chill of dread run down my spine when meeting them.
Occasionally, years later, what I 'felt' was borne out when they were arrested for some crime or other.
[usually involving children]
I can't really recall getting that 'feeling' off anyone obviously or socially considered "bad", such as street beggars or the like.
It's mostly from the "good" people.
Odd, isn't it?
[then again, it makes more sense to hide in plain sight, I reckon]