There is nothing in existence which God did not cause to exist. God is the Creator of everything that exists. Whether humans or animals or spirits, it is God who created them all. There should not be any doubt in the minds of those who are the children of God because such people should be fully aware that God is the one who causes everything that exists to exist. There is nothing that can create itself by itself. There is nothing that can exist without God knowing about its existence. The people that are existing in the world were all created by God. In the same vein, God created all the spirit beings existing on earth.
When we look around, we can see people who do not have the fear of God. In fact we have people who do not have human feeling. They are wicked in all their ways. What can we say about terrorists? What about cultists and assassins? Who created them? Can they create themselves by themselves? No, God is the one who created everyone. It is our personal character and attitudes that defines who we are. In the same way, God created angels to serve Him. But some of the angels rebelled against Him. Those are the ones who were cast down and they turned out to be demons.