Many have mistaken Satan for a "rival" to God, but in reality, he is only a creature and has very limited power.
Some religious traditions around the world have held the existence of two supreme deities, a good god and an evil god. These two gods are set in opposition to each other, and often break out in fights that impact the world.
Unfortunately, this belief has often spilled over into Christianity, so Satan is given a god-like status. People often believe that Satan could rival God in his power and is an equal match.
The Catholic Church clearly teaches that Satan is a creatureand God is the creator. God created Satan originally as a good angel, who then rebelled against his creator, choosing hatred and isolation rather than union with God.
Scripture and the Church’s Tradition see in this being a fallen angel, called “Satan” or the “devil.” The Church teaches that Satan was at first a good angel, made by God: “The devil and the other demons were indeed created naturally good by God, but they became evil by their own doing.”CCC 391
It’s important to note that Satan is a created being, receiving his existence from God. He is dependent upon God, who allowed him the free-will to reject God and his plans.
This means that Satan has limited power, given to him by God.
The power of Satan is, nonetheless, not infinite. He is only a creature, powerful from the fact that he is pure spirit, but still a creature. He cannot prevent the building up of God’s reign. Although Satan may act in the world out of hatred for God and his kingdom in Christ Jesus, and although his action may cause grave injuries — of a spiritual nature and, indirectly, even of a physical nature — to each man and to society, the action is permitted by divine providence which with strength and gentleness guides human and cosmic history. It is a great mystery that providence should permit diabolical activity, but “we know that in everything God works for good with those who love him.”CCC 395
Even though God may give Satan a certain amount of freedom to wreak havoc in the world, he does so for his own divine plans. We may not be able to see the beauty of his designs, but at the end of time, all will be revealed and we will see how even Satan’s actions worked out for the benefit of humanity.
Satan may seem imposing, but in the end, he is not a god and is on a short leash. If we ever feel threatened, all we need to do is cry out to God, who can save us and easily rein Satan back in and away from us.