Answer:
Satan was originally created by God. Before he became Satan, he was known as the anointed guardian cherub.
Ezekiel 28:14 (NIV)
“You were anointed as a guardian cherub, for so I ordained you. You were on the holy mount of God; you walked among the fiery stones.”
God created him perfect, without flaw, just like the other cherubim. But later, pride filled his heart, and he deceived himself into thinking that he could be like God—that he could receive worship as God. That’s when evil was found in him, and he refused to repent.
Ezekiel 28:15 (NIV)
“You were blameless in your ways from the day you were created till wickedness was found in you.”
When he rebelled against God, that’s when he became Satan. The word “Satan” means accuser or adversary, because he accuses human beings before God day and night.
Revelation 12:9–10 (NIV)
“The great dragon was hurled down—that ancient serpent called the devil, or Satan, who leads the whole world astray. He was hurled to the earth, and his angels with him.
Then I heard a loud voice in heaven say:
‘Now have come the salvation and the power and the kingdom of our God, and the authority of his Messiah. For the accuser of our brothers and sisters, who accuses them before our God day and night, has been hurled down.’”
Therefore, Satan was created by God, he rebelled against God, and in the end, he will be destroyed by God in the lake of fire after the final judgment before the great white throne.
Revelation 20:10 (NIV)
“And the devil, who deceived them, was thrown into the lake of burning sulfur, where the beast and the false prophet had been thrown. They will be tormented day and night for ever and ever.”
May the Lord keep us safe from the schemes of the devil.