How do we know satan is real?

You just have to believe in the Word (Holy Bible). He is real, very real. And so does Hell is real. He was a beutiful angel in heaven called Lucifer whose high position was to guard the throne of God. The sin of pride came into his heart. He wanted to be like God Almighty but in his madness, he enticed many angels to join him in an attempt to take over heaven. God threw Lucifer and all the rebellious angels out of heaven like lightning. These fallen angels became devils, and Lucifer became Satan. The Bible says that they settled around the planet earth, which became Satan's domain. So you see, most of the problems that now continue happen on earth is because of him. Satan is a real person and he only comes to steal, and to kill, and to destroy. But Jesus came so that we might have life, and that they might have it more abundantly. For this purpose the Son of God was manifested, that he might destroy the works of the devil.