We will need to compare two passages of Scripture to answer your question. In Isaiah 14:12-15 we will read about Lucifer (this is the only passage in the Bible that does mention Lucifer). In Ezekiel 28:11-17 we will read about the King of Tyre. I believe we will see that the SAME PERSON is being described in these passages and that Lucifer, who was once the most beautiful and wisest angel God had created, rebelled against God and “became the Devil and Satan.”

Isaiah 14:12-15: “HOW ARE YOU FALLEN FROM HEAVEN, O Lucifer, son of the morning! HOW ARE YOU CUT DOWN TO THE GROUND, You who weakened the nations! For you have said in your heart: ‘I will ascend into heaven, I will exalt my throne above the stars of God; I will also sit on the mount of the congregation on the farthest sides of the north; I will ascend above the heights of the clouds, I will be like the Most High.’ Yet YOU SHALL BE BROUGHT DOWN to Sheol, to the lowest depths of the Pit.”

Ezekiel 28:11-17: “Moreover the word of the LORD came to me, saying, ‘Son of man, take up a lamentation for the king of Tyre, and say to him, “Thus says the Lord GOD: ‘You were the seal of perfection, full of wisdom and perfect in beauty. You were in Eden, the garden of God; Every precious stone was your covering: the sardius, topaz, and diamond, beryl, onyx, and jasper, sapphire, turquoise, and emerald with gold. The workmanship of your timbrels and pipes was prepared for you on the day you were created. You were the ANOINTED CHERUB who covers; I established you; You were on the holy mountain of God; You walked back and forth in the midst of fiery stones. YOUR HEART WAS LIFTED UP BECAUSE OF YOUR BEAUTY; You corrupted your wisdom for the sake of your splendor; I CAST YOU TO THE GROUND, I laid you before kings, that they might gaze at you.’”

Most commentators would agree that the description of Lucifer by Isaiah refers to a mighty angel in heaven who had a great fall from heaven. In PRIDE he rebelled against God and desired to ascend to the very Throne of God in heaven where he would “dethrone God” and “sit on his own throne,” thus achieving his goal to “be like the Most High.” I believe the Lord Jesus referred to this great fall in Luke 10:18 where He said, “I saw Satan fall like lightning from heaven.” Jesus does not call him “Lucifer”; He refers to him as “Satan” (which means “adversary”). The apostle Paul refers to this same fall in 1st Timothy 3:6 when writing about the qualifications of an elder (overseer), “not a novice, lest being PUFFED UP WITH PRIDE HE FALL INTO THE SAME CONDEMNATION AS THE DEVIL.” Paul calls him the “devil” for Lucifer is known by both Satan and the Devil, as we see in Revelation 20:2, “He laid hold of the dragon, that serpent of old, who is the Devil and Satan.’

In Ezekiel’s description, we are told plainly that the “king of Tyre” was an “anointed cherub” which means he is AN ANGEL (see Ezekiel 10:1-14). We are also told that he had a GREAT FALL because of PRIDE. Ezekiel goes into more detail than Isaiah describing him. He was the “seal of perfection, full of wisdom and perfect in beauty.” These words could hardly describe a mere man and verse 15 confirms this: “You were PERFECT IN YOUR WAYS from the day you were created, TILL INIQUITY WAS FOUND IN YOU.” In other words, he was “perfectly sinless” till the day he sinned. His pride and rebellion caused God to humble him. Isaiah says, “How are you cut down to the ground.” Ezekiel says, “I cast you to the ground.”  Eventually Satan (the Devil) will be “cast into the bottomless pit” for 1,000 years and then “cast into the lake of fire” (Revelation 20:1-3, 10). He once had “the highest place in heaven” but because of his pride and rebellion he will have the “lowest place in Hell.”  (DO)  (595.3)