They were bound to this earth and they have lived here since the world was formed. They devote their sleepless, evil lives to harming God's people, deluding and harming others and generally wreaking havoc in the lives of all humankind. Whole churches can be brought down by hatred or bitterness, envy or backbiting, by evil angels. It is highly likely that the person is 'led by the nose' by demons. It is likely that they are the pawns of demons.
Demons are like stalking lions, watching for easy prey.
They are spirits, just as God is spirit. Under normal circumstances they cannot be seen, but they can assume human or any other likeness whenever they wish. This is how Dad or a favourite aunt can suddenly appear to you. Demons know what they look like, what they sound like and everything about their histories, right down to their pet names for you. So, they mimic them.