[Kataryn]

Originally Posted by Qilin

As for the scene with Irisviel in the end:

Spoiler for guess:

I'm going to take a wild guess and say that the mountain of corpses there represents all the failed homunculi that were produced before her. I mean, manufacturing homunculi than can serve as vessels for the grail can't be a 100% thing, right?

Spoiler for Irisviel corpses:

I'm pretty sure the drama CD released with the blu ray DVD explains a bit more. Jubstacheit (Acht) was telling Kiritsugu how Irisviel was the first successful model of Justeaze, I believe. Meaning he probably made a lot more models before but they were all failures. He also made a bet with Kiritsugu and said that if Irisviel doesn't pass the test to prove that she is a successful homunculus and dies, he can simply make another model.