[The Green One]

Spoiler for 73.1 guesses:

Well after resummoning all the Servants that were the cards from the series, which I doubt is an accident, they're probably going to be reforged into cards again, and Shirou will survive because the essence of the EMIYA card will be extracted from him to recreate the Archer card which will bring Kuro back, from some sort of imprint on the card, since the card was the catalyst of her existence in the world after all. As for how they'll bullshit Illya back into reality? Yeah... even my gerbil brain can't figure that one out.