Look guys Satan is a fallen angel. His name was Lucifer and ....
I couldn't let this one go undiscredited - sorry.
Even if you believe the fallacy of a supernatural devil the name Lucifer has nothing to do with it.
The name lucifer (is referred to twice in the Bible though you will only see it once in many Bibles as there is doctrinal bias in some versions).
The name means 'morning star' and is a title of adoration. That is why the other times it is used (translated two different ways in greek) it's about Jesus (1Peter 1:19, Rev 2:28 and Rev 22:16).
In the passage in Isaiah it is being used to show how Nebudcanezzer was big and powerful. Made so by God (i.e. metaphorically in heaven).
The whole of the Bible around that part of Isaiah is all about Babylon and it's king.
It is all about how the king was made high and powerful and took over many countries but then wanted to be higher still. It is about the huge statues he made of himself that others should worship (remember Daniel).
It was all about how God would bring him down. It was about how God would have Babylon taken over by the Medes.
Please read the 3 chapters together Isaiah 13-15 : reading verses of the Bible out of context leads to the type of mistake you have been taught.
As Wesley put it
Lucifer - Which properly is a bright star, that ushers in the morning; but is here metaphorically taken for the mighty king of Babylon.
Even Gill and Gusik (folks who believed in the devil as a supernatural being) state this is
not about the devil.
Gusik does point out though that in his opinion "the king of spiritual Babylon, Satan"
Letting go of this error does not stop you from clinging to your error about a fallen angel called the devil.
But using the name lucifer in this way is to ignore the Bible in favour of the teaching of men and it's an error that is just too obvious if you
read the Bible around the verse.