[Marsh.]

Originally Posted by Glenn.

Do I believe JK knew this about Nagini from the beginning? Yes. She is and was absurdly thorough when planning this story. You would have to be, as it’s a complex story.

Tbh I do too. I remember all of the interviews she used to give between each book and the old website she used to update with trivia and you could submit questions for her to answer. She had amassed a ridiculous amount of detail in the backstory she created whilst writing the HP books.