Some years back there were some public comments from famous authors about the Susan in the Narnia books not being present for the Final Battle and what followed. It was framed as bigotry against women and people of average morals.
Neil Gaiman's came in the form of a short story, "The Problem of Susan," which from an excerpt I found is apparently quite vile.
Gaiman has fallen out of public favor as allegations against him have begun to surface.
Two other authors were J. K. Rowling, who ought to know better, and Phillip Pullman, who also writes vile stories, I've been told.
Pastor Douglas Wilson has a lucid, sensitive, and rather long rebuttal to the Problem of Susan; link below.
My own, lesser contribution here, is that C. S. Lewis was a fan of George MacDonald, and MacDonald wrote some vivid portrayals of spiritual devolution. In The Princess and Curdie, Curdie was given the ability to discern which beast a person's moral character was descending into by holding their hand. In Lilith, MacDonald reveals that the dull and brutish big ones/giants were immature persons who chose wrongly too many times. Their bodies grew larger while their selves grew smaller.
Susan being "no longer a friend of Narnia" is a succinct description of Susan not being anywhere near all that she should have been. It is not final, however; she is in spiritual peril, not perdition.
EDIT: That last sentence is not quite where I want it to be; Susan is lost, but not yet irredeemably so.
https://dougwils.com/books-and-culture/the-salvation-of-susan-pevensie.html
There is much to be gleaned from old books. Today I learned that the cutting to pieces of Rahab in Isaiah 51 can be understood as part of God's work in parting and securing a passage across the Red Sea for the escape of the Israelites from Egypt.
They weren't just fleeing the Egyptians; there were principalities and powers at work then, just as now.
The Israelites were significantly reminded of the Red Sea passage as they entered the Promised Land, Joshua 4 says, when God stopped the flow of the Jordan River for them to cross over.
There's also the prostitute Rahab who assisted the Israelites, whose God had easily defeated her namesake.
"Three souls flying home because I stayed behind"
One of the souls I've helped toward salvation suddenly flew home recently. This song helped me to really cry for the first time over it.
I happened to read about the Gadarene swine in Mark 3 this morning before coming across this piece, which mentions it.
David Clements mentions Michael Cocchini. A quick internet search tells me that they've worked together before, and that a different Michael Cocchini--and a Susan Clements--went fatally missing in the Smoky Mountains. At separate times.
Feels like a rabbit hole.
Much like Jonathan Cahn connects the major demons of ancient Israel to today's United States, Clements says that the spirits of the Nephilim are here and active.
https://joehoft.com/attorney-david-clements-mkultras-shadow-a-demonic-war-for-humanitys-mind/