I'm watching Prisma ilya Zwei and got to the confrontation between Kuro and her mom and they don't explicitly state where she came from or what she is. I vaguely remember Ilya is a manufactured grail from FSN. I didn't play FHA or Zero so I don't know what the point of all the Luvia/Maid/Kiritsugu wife stuff is.

Where did Kuro come from? or post Kuro/Ilya reaction images.