I'm the anon from last thread:
The Original Sin was Adam and Eve eating the Fruit of the Knowledge of Good and Evil, gaining the ability to know right from wrong and to question what they were told (and, more importantly, to know right from wrong and then choose to do wrong still). For this, they were cast out of the Garden of Eden, and as punishment were made mortal and forced to "Toil to grow seed from the fallow earth." (in other words, they would have to labor and struggle to live, instead of dwelling in Eden where life was without cares.) The stain of Original Sin taints all men, making them mortal and full of needs while also giving them the power to know what is right and what is wrong.
Charlie's dad is Lucifer, who is one of (depending on the source, the ONLY of) the Fallen; the angels who rebelled against God and lost. Angels, even fallen ones, definitionally cannot have Original Sin. Her mom is Lilith, the first woman, who got kicked out of Eden but WASN'T stripped of mortality for refusing to submit to Adam's will. Therefore, Lilith ALSO lacks Original Sin. QED, Charlie lacks Original Sin.
What does this mean?:
-Charlie is not mortal: in all likelihood she wouldn't be moral even IF she had Original Sin given her parentage, but it bares repeating.
-Charlie has no needs: That is, she doesn't need to eat, drink, breathe, or sleep. She also presumably doesn't get physically tired.
-Charlie lacks a conscience: Although she is very much a good person, because she doesn't know how to do wrong, she also doesn't really UNDERSTAND what Right is, either. Her innocence is naturally coupled with naivete.