I still think its Yashuu's fault, like the others said, she took her job way too seriously,
I think when you're dealing with forces that can wipe out an entire household full of people and continue to spill out into the rest of the world even after every possible action has been taken to contain it, it's not possible to take your job "too seriously". If you're charged with managing a warehouse full of volatile explosives and you turn a blind eye to some ignorant fool walking in there with an open flame, I'd consider that negligence.
she still knew right from wrong and probably knew what would happen if he killed kaname right there and then. :|
That just... doesn't make sense, though. Yashuu's entire life was devoted to making sure the Unleashing would never happen; that's why she was so strict about keeping the rules. If she knew what was going to happen and killed him anyway, that would make her more than misguided, it would make her evil and crazy.
I always felt really sorry for Amane because i feel like she had nothing to do with what happened (she was just a kid and couldn't have known better) and yet she was impaled. Kinda cruel, if you ask me :|
She made the decision to break the most important rule that had been taught to her all her life. How can you say a kid couldn't have known better, when we have Shigure and Hisame as examples of children who did know better? Kids do know when they're breaking rules, even if they don't understand the exact reasons why the rules are in place (and I think in this case all the Handmaidens did). I won't argue that the impalement wasn't cruel, but it wasn't done for the sake of cruelty. Once the Unleashing had happened, pretty much everyone in the shrine was guaranteed to die cruelly, not to mention a lot of completely innocent carpenters. Which, again, is why Yashuu was so ruthless, in our eyes, about trying to make sure it never would happen.