These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
"I've shown you mine, so the least you can do is show me yours" and "I am the bone of my sword."
Saber once tells Shirou "you've entered me so many times"... referring, of course, to the fact that he's entered her memories.
Another good one from Saber, to Shirou: "You were my sheath." She's discussing the fact that he's a vessel for Excalibur's sheath Avalon, buuuuut...
Lancer's Gae Bolg...or, if you prefer, his "Gay Bulge"
Anti-Climax Boss: Caster in Fate, Rider in Unlimited Blade Works, Rider's first fight, both of Caster's fights, Sasaki Kojirou, AKA Fake Assassin, normal Berserker and Gilgamesh in Heaven's Feel.
Author's Saving Throw: While probably not its primary purpose, the Last Episode removes any horrifying implications that Shirou becomes Archer after the Fate route. Adding to that, it was specifically made because Takeuchi begged Nasu to not let Saber have a Bittersweet Ending.
Complete Monster: Zouken Matou was an ancient mage, the ruler of the noble Matou family. Zouken Matou allowed Tokiomi Tohsaka to foster Tokiomi's younger daughter Sakura with the Matou family, but Zouken proceeded to allow her to be spiritually violated by magic worms to control her, later gloating to Sakura's would-be protector and Zouken's own kin Kariya Matou about the worms that fed on Sakura's purity. To keep Sakura's budding dark side in check, Zouken had his "grandson" Shinji rape her regularly and fostered Shinji's descent into evil. It was revealed that Zouken was far older than he appeared, staying alive by bodyjacking people and sacrificing others all with purpose of obtaining the Holy Grail.
Gilgamesh can sometimes fall into this, with the fanon portrayals of him that tone down his Jerkass qualities considerably and put him into a much more positive light, in addition to some who ignore that he quite frankly wants to rape Saber, doesn't care about her consent and seems to even prefer her resistance. At times, his Attempted Rape of Saber is explained away by being purely attempted and not being something that succeeded, yet despite that, Shinji is strung up by the fandom for the same action. note Of course, he is (quite rightly) strung up not just for that particular attempt but for his other actions, including successful rape; but this comparison does apply. One must note that in both the original myth and the game Enkidu originally fought him due to him invoking Droit de seigneur, or the lord's right to a bride's virginity, where the consent of the woman didn't matter, and Values Dissonance can't be invoked with this because even in the original myth people thought he was going too far.
Kotomine can also fall into this, as he is actually one of the most popular characters in the franchise and has an incredible amount of depth to him due to a very believable backstory while still being vague enough to spark discussion about his character. Is he a Tragic Villain or a Woobie, Destroyer of Worlds?
Die for Our Ship: The Saber/Shirou fans are really, really threatened by Sakura's presence. Is it any wonder that several of them double as Sakura bashers?
This actually cuts both ways, with Sakura fans usually demanding Saber's removal from the equation. This has its roots in two things. Firstly, Sakura and Saber are both characters that Shirou feels he needs to "save" in their respective routes, and their circumstances mean it's difficult to do both. Secondly, in the canon routes, Saber gets turned evil and mercy killed by Shirou in HF while Sakura is promoptly forgotten about in Fate.
Rin doesn't have this problem thanks to UBW having the only actually listed Good End in the game and her character being rather ... open to these kinds of things.
Speaking of Rin, Sakura fans tend to bash her for being Shirou's love interest in Unlimited Blade Works.
Lancer, who really gets The Worf Effect very hard in the series, but his wit, amiable and likable personality, and interest in fighting compared to the more goal oriented and ambitious Servants made him easily one of the most popular Servants. His glorious sendoff in Unlimited Blade Works with killing Kotomine after the latter ordered him to commit suicide is very satisfying as well.
Fake Assassin AKA Sasaki Kojirou is fairly popular due to being a quite likeable nobleWorthy Opponent towards Saber, his distaste and snarking at the less popular Caster, and his Warrior Poet nature.
Fanfic Fuel: Because Archer's Dark and Troubled Past is only told in broad details rather than real specifics, plenty of fanfic writers like to write about what really happened in his life. In particular, because Nasu says that Archer can come from any potential timeline (even one of the three in-game ones), as well as the fact that Archer has a damaged memory (so he can't remember any specific details or characters he encountered in his timeline), Archer's practically a fanfic goldmine.
The "I am the bone of my sword" invocation/chant for the Unlimited Blade Worksreality marble isn't given much weight or attention, and only seems to be there for the Rule of Cool. Until the Heaven's Feel route, that is, where its meaning becomes painfully clear after Shirou uses Archer's arm for projection, catapulting him past his limits and resulting in an eventual rebound that reforges his body into thousands of swords, killing him from the inside out."I am the bone of my sword" indeed. At one point in Unlimited Blade Works, Archer tells Shirou and Saber that he lost his arm the first time he used a projection, which seems to be a lie as Shirou is able to perform projection and still manages to keep both arms throughout both Fate and UBW. But then in Heaven's Feel, Shirou has one of his arms blown off. Archer voluntarily has one of his arms grafted to Shirou, and "losing his arm" at this point enables Shirou to perform Projection for the first time not long after.
Also, Sakura's jealousy. Cute? A funny little argument with Rider about Shirou finding her attractive? Not so much after killing Shinji, going berserk and hitting you with the worst bad ends of the game plus her Villainous Breakdown against Tohsaka at the end, where it's also revealed that no, Sakura did not pick up the little cues that Tohsaka really did care about her all along.
Remember the humorous scenes you can get if you nag Saber for "a super move that can defeat a Servant" during training? In one ending of Heaven's Feel, Shirou actually wins against Saber Alter... by using Archer's super move with Kanshou and Bakuya against her. Though maybe it's just Hilarious in Hindsight, since that ending is actually really, really awesome.
Shirou is a somewhat dim man with red hair who is obsessed with swords. Sound familiar?
In the Fate route, Rin half-jokingly speculates that Archer must have been a skirt chaser back when he was alive. Then comes UBW and we discover who he is. Suffice to say, he didn't chase skirts as much as he was chased by skirts.
Mis-blamed: As noted in the Complete Materials, Nasu didn't actually write the infamously bad sex scenes in this or any other Type-Moon game. Hasn't stopped 'Nasu can't write sex' from approaching Memetic Mutation levels - that may, admittedly, be true, but we can't say for sure without any evidence.
Moe: Sakura and Ilya stand out as the most notable cases, although Saber and Rin have their moments.
Shinjistarts out as a Jerkass, but crosses the line in every route. In Fate it's trying to kill off the entire school to power up his Servant, his laughing in Unlimited Blade Worksas Gilgamesh rips Ilya's heart out is cruel, but with his Attempted Rape on Tohsaka he crosses the line. And then we find out in Heaven's Feel that he's raped his sister many, many times before the story begins.
Kotomine using the orphans of the Fuyuki City fire as living prana batteries for Gilgamesh, though we only find out about it in the Fate route. And this could have happened to Shirou.
Gilgamesh himself, if his description of what he plans on doing to Saber in the Fate route isn't sickening enough, he crosses it by destroying Ilya's eyes and ripping her heart out without a shred of remorse in Unlimited Blade Works.
In Heaven's FeelSakura Matou herself does not cross this, despite killing and devouring hundreds of people, because she does so subconsciously and is unaware that she is doing it. However, when her dark side rapes Rin in the "Femme fatale" Bad End, even Shirou (who has sacrificed everything for her) realizes that she's too far gone to be saved. And in Fate/unlimited codes her dark side crosses this by keeping Bazet alive just so she can watch her suffer.
MST3K Mantra: This is essential for any of the hardcore fans who are addicted to the intricacies of canon to enjoy the movie at all. Never mind the complete excising of Shirou and Rin's opposition, for instance, just focus on the epic action scenes.
Narm: Two words: Gay Bulge. (from the anime dub pronouncing Gae Bolg in the worst possible way.)
One True Threesome: There are two, Shirou/Saber/Rin and Shirou/Sakura/Rider. First is played straight by Unlimited Blade Works route and completely fulfilled in Good End of this route. Second is slightly hinted in Heaven's Feel route. Both are expanded at various levels in Fate/Hollow Ataraxia and many other associated works or materials and very popular in fandom.
In Unlimited Blade Works, Ilya's death might not have carried as much weight were it not for the fact that you have to play through Fate first (where you befriend her), and watch a particularly heart-rending interlude first.
Heaven's Feel has six simple words: "Save Saber"/"Bring the knife down." Guess which one is the right choice. The Good Times Montage and the music that accompanies that particular scene makes it hurt even more. Way to twist the knife there, Nasu.
Vanilla Protagonist: Shiro has no history of mages or any desire to compete in the Holy Grail War. This makes him contrast with the other mages, whose pasts are colored by generations. It's Played for Drama later in the story, where the player realizes he's so vanilla because he's a borderline Empty Shell. He lost any sense of self and identity in the fire and is essentially dead inside.
Values Dissonance: At one point, it is revealed that Rider feels insecure about being too tall for a girl. This is an issue that a lot of real life girls can relate to... Except for the fact that Rider is only 172cm tall, which depending on where you live, could be considered as rather short. More than value differences, it shows the differences in height standards between different societies.