Into the Wardrobe

"Night Demon" is the correct translation of nightmare, and a nightmare, according to the version they don't tell children, is a demon who rapes a person while he/she is asleep. The Latin words for this kind of demon are incubus and succubus, though lamia is sometimes used too. So lilith may be the word for "nightmare" in the original sense. This gets both the sense of demon and sexual partner. Maybe the Medeival writers were trying to come up with a myth that explained why Lilith was both sexual and demonic, so they hit on the idea of a rebellious wife of Adam.

As usual, there are some contradictions between the books.

In The Magician's Nephew, the people of Charn appear to have been human although it is mentioned that the royal family was believed to have some giant blood (which appears to account for Jadis' tremendous physical strength, a quality of hers far more prominent in TMN than in TLTWTW).

I need to re-read CON especially LWW & MN....

Is the reference to "Giants Blood" actually made in MN by Jadis? or is it as I suspect a statement made by Mrs Beaver?
But whichever makes the comment, it would still probably be propaganda in one form or another.. An attempt to be intimidating by Jadis, and an attempt to be derogatory by Mrs Beaver.

Personally I would take the view that the inhabitants of Charn are actually Human descended (as per my heresy) BUT thats just my own view.

As to the character of the sister of Jadis, well we only have the word of Jadis as to what she was like.
Again its just part of my Grand Heresy, but I prefer to take the view that the sister was actually honourable and was fighting to try to save Charn. (I could expand on that, but I've already done so in my Grand Heresies.. so I won't)