I don said:
I watched Zero before watching S/N. Yes, the ending of Zero is pretty bleak, but more importantly I feel cheated when the grail pulls a reverse card, and there is no explanation or any sort of clever meaning to justify it. It's like watching your daughter win a tennis championship, but then they give the trophy to the other kid because his dad is rich and a school chairman. Oh, also your daughter is now dead, but here's some random punk for you to take care of.
That's definitely the biggest weakness of Fate as a franchise. It's extremely continuity locked. Main entries in the series tend to just assume that anyone who sees them is familiar enough with everything that's come before, including branches of a never-imported visual novel that are only now starting to get anime adaptions, or plot points from that *other* visual novel that never got imported... and don't explain beyond the bare minimum they feel they need to.
"Well, obviously the Grail is evil! See, back in the third Holy Grail war, a random fluke caused this guy to be summoned who was basically tortured by everyone he knew and loved so he could become an avatar of an ancient Zoroastrian god of destruction, and going though all that left him with a little bit of a grudge... and when the holy grail reabsorbed him it assimilated that grudge into itself, so now it has no interest in granting the wishes of others unless they inflict suffering upon as many people as possible! We made it so very clear!"
Here's the problem. Fate Zero's message is terrible. The show says, "Don't be a hero, being a hero is a childish dream." In reality, if you have to kill people to save people, you should. It is not some tragic paradox, it is common sense.
The show tries to explain itself an easily solvable utilitarian paradox. Kiritsugu has to kill everyone on the 200 person boat holding him hostage to save another 300 person boat. Killing all 200 people seems harsh, but everyone on the 200 person boat would have killed 1.5 persons, whilst everyone on the 300 person boat would have killed 0, considering it was Kiritsugu's decision, not him being held against his will. Everyone on the 200 person boat is at face value incredibly selfish, and has forfeited their lives.
Then the grail tries to pull a fast one, and says that the 300 person boat splits into 100 and 200 person boats, the 100 person boat holds Kiritsugu hostage, and the process repeats. Kiritsugu kills all 100 people again, but then again everyone on that boat would have killed 2 persons. Now you're left with a boat with 200 people who killed 0 persons.
Which choice is better, saving 200 people who killed 0 persons, or 200 people who killed 1.5 persons? Hmmm, what a difficult decision. I know what I'd choose, not the boat filled with selfish bastards.
It wasn't heroism that was a childish dream though. Saber's arc in Zero is the same as Shirou's is S/N, She mistook her own guilt complex and desire to be punished for her perceived past injustices as some kind of selfless heroism. She dressed it up as though her wish for the grail was a noble and knightly act of valor, when she really just felt like she deserved to self-flagellate for the crimes she felt responsible for. Kiritsugu did have choice words about knightly honor and heroism... but the whole point of his character was that he wanted more than anything to be like her, and his character was motivated almost entirely by self loathing. Admittedly, since Saber and Shirou don't get their proper arcs until the sequel series, Saber's arc in Zero is kinda just brought up and then left in a less-than-satisfying manner.
The point of the exercise with Kiritsugu and the boats was that the Grail was willing to give him the power to always be the one to choose who lived and who died. He could go on living as he always had, killing the few to save the many, on a grander scale than ever before, but there would never be a time when that role was finished. He would constantly be acting to save a gradually smaller and smaller portion of people, who in turn would grow to resent him for the power he had over them.
It basically comes down to being Kira from Deathnote... Except, humans, not being great creatures, would never reach the idealized state Kira believed his killings would eventually create. Kiritsugu would suffer as he spent the rest of his life performing the same act he initially sought the grail to try to avoid ever doing again, the populace would suffer as a random dude used divine power to constantly judge them guilty, and the grail would be happy... because the grail gets off on suffering. This was how Kiritsugu realized the grail was corrupted, and why he decided to destroy it.
...except, it turns out, there are consequences to deciding to blow up a magical artifact whose soul defining characteristic was that it contained an unprecedented quantity of magical energy so... good job, Kiritsugu.
Sorry, I'm not really trying to sway your opinion or have a passionate argument... It's not as though I don't understand where your criticisms are coming from, or believe that Zero was a flawless series. I just so rarely get an excuse to talk about Fate Zero, so I gotta take my chances when I can!