Remember how in the Matrix, agent Smith used to jump from body to body, trying to find and kill Neo? Monitoring spirits and demons follow you everywhere you go, because of the light you possess. They find the weakest vessels to occupy; people who are not protective of their energies and do not care to clear themselves of negativity. People with bad spiritual hygiene... Who are closest to you, so these entities can gain access to you and defeat you through being a low vibrational being.