Damn, telegraphed since the chapter of "death". So much for so little...
I think that it was an option but wasn't planned and they were forced to add it to give the daughter powers. So she could fight and be a main character. Of course whether I am right or wrong, this is very by the numbers and generic.
Sorry wasn't sure anyone was going to comment
Honestly, it not much of a problem one could already guess it would happen from last chapter and once you talked about spoilers (which means it was something that either interested or pissed off people enough to talk about.) It was clear what it was. I more just reminding of my policy of not looking at spoilers till the summary so it is an honest reaction and thought at the time. Then edit to fix mistakes. I needed to do something yesterday so I had to cut the ending short and come back to it.