When someone acts like a demon, then he is a habitat of demons. We are influenced by the kind of spirit that is inside of us. Demons are spirits and they take on the forms of their host bodies. The dwelling place of a spirit is whatever body that such spirit chooses to dwell in. This is why we should not allow ourselves to be possessed by an evil spirit. We must be possessed by the Holy Spirit. The Holy Spirit is the spirit of God. As children of God, we ensure that we are not possessed by the spirit of the demons but rather, let us be possessed by the Holy Spirit.
Demons exist everywhere. It is not that the devil is omnipresent but it is because the demons are in multitude. The number of demons on earth is numerous. These demons are the fallen angels which were cast out from heaven. The quantity of these fallen angels is much. The demons are still existing on earth. They have not been bound to the bottomless pit. According to what is written in the Bible, their time has not come.