Disclaimer: I do not own The Kane Chronicles nor do I own Egyptian mythology. If I did I'd be a lot richer, fatter, and way older.
Lamentation
She's doing this for his own good.
It's not like he'll see it that way, though. He'll see her act of love as an act of betrayal. What he won't understand is that this hurts her too, a double edge sword of deceit and lies. Set would never understand that she still loves him, even after everything, even after all he's done, after all she's done. Their bond is still strong and real, even though it is not as clear as it used to be.
Set was a good husband, attentive and kind to her, but his recent actions have not been wise. He knows this, but he still refuses to see the wrong in his actions. If he really believes that killing their brother Osiris is the best way of things then he is deluded. Isis will have his head on a platter.
What she has done will make him see the error of his ways, and if it does not, well, he will hate her for the rest of eternity. His time spent in the Duat will probably be spent on creating a plan to find and annihilate her. It's such a long to hate her.
But perhaps one day he will know that what she did was for him and not for anyone else (especially not herself), but she doubts it. He was always blinded by his own self interest even as a child.
But if her acts have stopped chaos from ruling, well, isn't that the smart thing? Won't Set see what she has done is a good thing?
He has not yet noticed, and hopefully he will not. Nephthys just wants to be away from him before he realizes her treachery.
But when she hears his roar of anger and anguish she knows that she has not been fast enough.
A/N: Why is this not in the Mythology section of ff? Because TKC is the only place that I have ever heard of Nephthys betraying Set (or something like that) and I didn't feel comfortable putting it there, so I put it here. I am very interested in this subplot. I want to know what she did! Because I know it was for Set's own good, even though he hates her. Do you guys have any theories? I'd love to hear them!
And just in case you're wondering I chose the title because Nephthys was the goddess of lamentation and something else, I forget which.