Fate/Zero was released in the fall of 2011 and is widely considered to be a stand-out series. Ranking in the top 100 anime on the site MyAnimeList, the show is praised for its dark and serious tone and themes.
Despite being so popular, the ending of Fate/Zero may leave many viewers incredibly confused. This is because the show is a prequel to the visual novel Fate/Stay Night. As a result, there is lots of important information omitted that is necessary to connect all the pieces. This explanation provides some of that missing information and answers some questions that many viewers may have.
Why did Kiritsugu Reject the Grail?
Despite all the tears, sweat, and blood Kiritsugu put in to achieve the Holy Grail, in the end, he rejects its wish-granting powers. This pivotal moment is incredibly soul-crushing as all of Kiritsugu’s efforts and sacrifices were for nothing. The reason why is because of how the Holy Grail works.
The Holy Grail is presented as an omnipotent wish-granting device, similar to a genie in a bottle. However, this is not how the Holy Grail works in Fate/Zero. The Holy Grail is a gateway to an unlimited magic source, allowing any mage to perform incredible miracles. This also means that the victor must know how to achieve the wish since the Holy Grail is only a power source.
Throughout the series, Kiritsugu commits terrible acts in the name of the greater good. Because this is all Kiritsugu knows, he can only achieve his wish or peace through killing. Additionally, because the grail is corrupted, it can only grant wishes through destruction.
Why was the Grail Corrupted?
The reason the grail was incapable of granting Kiritsugu’s wish is that it has been corrupted so that it can only grant wishes through destruction. The reason for this stems from the Holy Grail war prior to the events in Fate/Zero. That Holy Grail war was known as the 3rd Holy Grail war and took place in the 1930s.
In the 3rd Holy Grail war, one faction attempted to subvert the system and summon the Zoroastrian god, Angra Mainyu. To summon such a powerful being, a brand-new Avenger class was created to replace the Berserker class. Angra Mainyu was supposed to be a living calamity that would win the war by sheer force but ended up being so weak that it died on the fourth day.
Angra Mainyu was such an abstract concept that it failed to summon any actual God. Instead, it created an entirely new being. Angra Mainyu is supposed to represent ‘all the evil in the world’, and so the desire for such a being to exist is what ended up being manifested. This wish for the manifestation of ‘all the evil in the world’ not only created a servant but also became engraved into the Grail. Thus, the Holy Grail became corrupted.
What Caused the Fire at the End?
After Kiritsugu rejects the grail, he orders his servant Saber to destroy it. Saber, using her most powerful move, breaks the Holy Grail causing all of its contents to spill out. Due to Angra Mainyu’s corruption, the contents within the Grail only bring destruction, partially leading to the devastating fire.
However, the Grail was not able to bring such destruction on its own. As the contents of the Grail spilled out, it engulfed both Kirei and Gilgamesh. With its power, the Grail was able to revive Kirei and select him as the victor over Kiritsugu. Then, through Kirei’s wish, the Grail was able to bring destruction in the form of a tragic fire.
How Does This Impact Fate/Stay Night?
The conclusion of Fate/Zero ends up impacting a significant portion of Fate/Stay Night and its characters. First off is the rebirth of Gilgamesh, allowing him to exist after the Holy Grail War has been completed. This is what allows him to make an appearance 10 years later in Fate/Stay Night. Additionally, because Gilgamesh was reborn through the Grail, it also corrupted him, which is why he changed his wish to exterminate most of the human population.
A similar change also occurs to Kirei, though it does not corrupt him. Instead, Kirei becomes interested in the outcome of the Grail’s destruction and seeks to understand both his own wish and Angra Mainyu. His primary motivation in the Heaven’s Feel route is to rebirth Angra Mainyu and unleash it upon the world.
Most importantly, the destruction directly ties into the main protagonist of Fate/Stay Night, Emiya Shirou. Shirou is traumatized by the destruction that occurred as a result of the Grail and becomes his motivation to participate in the Holy Grail War. He is determined to prevent the tragedy from happening again.
While Fate/Zero has a somewhat convoluted end, having this extra information clears up some confusion. Of course, it does not explain everything. The Fate Series is incredibly complicated with its own extensive dedicated wiki. However, this should be enough to make sense of the ending of Fate/Zero.