That's not in the Biblical canon but comes mostly from Heiser and the Pseudipigrapha (not that I disagree with Heiser...he has done an incredible amount of good work on the subject).
That said, the term "demon" is defined differently by many different theologians and Biblical scholars. Even the term "angel" (messenger) doesn't capture all the spiritual beings that exist. The term daemon used to be used to describe those spiritual beings between God and man.
The term demon is often used loosely to describe any non-corporeal or semi-corporeal being of an evil nature.
BTW, there is much that the Bible doesn't tell us. As many theologians have said, it is written on a need-to-know basis. Jesus told us that many of his sayings will not be understood except by those with "eyes to see."
Many of the things Jesus did are not included in the Bible:
John 21:25: Jesus did many other things as well. If every one of them were written down, I suppose that even the whole world would not have room for the books that would be written.
That’s not in the Biblical canon
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Says you.
You say a lot of unbiblical things though.