Nothing will exist except God calls it to exist, so the existence of everything depends on God Almighty.
Acts 17:24;
The God who made the world and everything in it is the Lord of heaven and earth and does not live in temples built by human hands.
It is God that made the world and everything therein, everything in the entire universe. We must understand that when satan was created, he was not created satan, his name was not even satan( satan means adversary, enemy, the arch-enemy of God).
So how did satan become bad because in his original being, after creation, he was an angel.
Isaiah 14:12-14;
12 How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations!
13 For thou hast said in thine heart, I will ascend into heaven, I will exalt my throne above the stars of God: I will sit also upon the mount of the congregation, in the sides of the north:
14 I will ascend above the heights of the clouds; I will be like the most High.
But his ambition made him an enemy of God because he wanted to be equal with God, and so he was thrown down from heaven, excommunicated, cast out. Also demons were not created demons, they are fallen angels. And why are they called fallen angels? Jude 1:6;
And the angels which kept not their first estate, but left their own habitation, he hath reserved in everlasting chains under darkness unto the judgment of the great day.
They are the angels who followed the rebellion against God, that is why they became demons. They are spirit beings, they do not multiply, they do not reproduce after their kind. They can't multiply like humans. Revelation 16:14
For they are the spirits of devils, working miracles, which go forth unto the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty.
Their disobedience to God turned them from the angels of God to the angels of satan.
And we also must know that satan and his demons are waging war all the time, against God's creation and kingdom. Christians should never underestimate the knowledge of these evil beings which are not limited to just a few years but before the origin of man. We need God,we need faith in God to be able to combat with satan and his angels.
Ephesians 6:12;
For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places.
I am 
