History Fanfic / InPursuitOfASingleIdeal

** Illya's status as a KidHero gets brutally deconstructed. While she is magically gifted and a hard worker who wants to cooperate with others, her positive qualities absolutely do not counterbalance her naivetie and ignorance. Her entire motivation for her hunting the Class Cards is that she wants to be a magical girl, and she is the only one who has no idea just how big the stakes really are. In addition, several clues that other people pick up completely go over her head, [[spoiler:and she doesn't even register TheReveal that she's a {{Homunculous}} because she's too confused to understand the situation]]. On top of that, because of her age, the other characters ''do not want'' to explain her situation to her which means that she has even ''less'' understanding of the severity of the situation, and from her point of view [[spoiler:Shirou]] treats her badly for no real reason. She only understands just how much danger she's in when [[spoiler:Shirou and Grey almost die at the hands of Emiya Alter]].

** The hotel where Kayneth stayed at still turned into a pile of rumble.

* InternalReveal: Basically everyone's secrets come crashing down once [[spoiler:Shirou finds out that Illya knows about the class cards. This includes stuff like the Einzberns being Homunculi, the real reason why Grey is in Fuyuki, and Kiritsugu telling Shirou about Shirley]]. The only one's whose secrets have NOT been revealed are Miyu's and a good chunk of Grey's.

* MirrorMatch: [[spoiler:The Grey vs. Artoria Alter match turns into this, as Grey loses more and more of herself over the course of the fight to the point that she emmulates Saber's style perfectly.]]

* NotWorthKilling: The entire reason that Waver survived what would have been the Grail War ten years ago. [[spoiler:Kiritsugu noticed him after killing Tokiomi but decided that he wasn't worth the effort since he wanted to prioritize going after Kirei.]]

** Waver has issues with Rin due to her association with Fuyuki. However, even he couldn't bring himself to tell her about [[spoiler:how her father died to Kiritsugu]], partly knowing that it would shatter her and partly because she was uninvolved and he didn't want a repeat of what would have happened to[[spoiler:the Mackenzie family.]]

** Kiritsugu built such a reputation as a MageKiller that even the Kaleidosticks are familiar with his methods. [[spoiler:Waver, who saw him kill Tokiomi]], has actual nightmares about him.

** We are given very few details regarding how exactly Irisviel and Kiritsugu stopped the Fourth Holy Grail War. There is the obvious "Iri, Illya, Sella and Laysrit don't live with the Einzberns anymore", but beyond that the information is little more than... snapshots. We know that Kirei is alive even though he was a participant, [[spoiler:Kiritsugu killed Tokiomi and Kayneth]], Waver [[spoiler:made it to Japan and saw the above murders]], and the hotel in which Kayneth resided in during ''Zero'' still ended up blown up, but no information on who did it or if Kayneth was in the building. All of this poses the question on both how and ''when'' did Kiritsugu decide to end the War.

** The second Assassin card is shown to be able to manifest as many heroic spirits, including but not limited to [[LightNovel/FateApocrypha Jack the Ripper]], [[VideoGame/FateGrandOrder the First Hassan]], and even [[spoiler:Counter Guardian Kiritsugu]].

* DiesDifferentlyInAdaptation: In ''LightNovel/FateZero'', Tokiomi was killed by Kirei, who then tried to shift the blame to Kiritsugu. In this fic, [[spoiler:Kiritsugu really did kill Tokiomi, and Waver was an eyewitness]].

''[[https://forums.spacebattles.com/threads/in-pursuit-of-a-single-ideal-fate-kaleid-liner-prisma-illya-au.935013/ In Pursuit of a Single Ideal]]'' is a crossover between ''Manga/FateKaleidLinerPrismaIllya'' and ''LightNovel/LordElMelloiIICaseFiles'' written by [[https://forums.spacebattles.com/members/knightoftheend.319791/ KnightOfTheEnd]]. It's hosted on Website/SpaceBattlesDotCom and [[https://www.fanfiction.net/s/13920638/1/In-Pursuit-of-a-Single-Ideal fanfiction.net]] - however, that version is not currently up to date.

* AdaptationalPersonalityChange: In the source material, Illya was a fan of the MagicalGirl genre, but she wasn't a fan of being an AscendedFangirl and at the beginning she went through a phase of IJustWantToBeNormal. Here, Illya goes to the exact opposite route of IJustWantToBeBadass and is ''extremely'' excited to be a magical girl.

* InexplicablyAwesome: [[spoiler:Shirou imitates Muramasa's fighting style from ''VideoGame/FateGrandOrder''. However, in ''FGO'' Muramasa is entirely reliant on Shirou's Reality Marble for his abilities. THIS Shirou has no reason to have a Reality Marble, because his parents died in a simple accident instead of the dramatic ending of ''LightNovel/FateZero''. So who exactly is the source of Muramasa's skills ''now''?]]

** The fight against Diarmuid takes place at the site of the hotel his masters were staying at in ''LightNovel/FateZero''.

* NotMeThisTime: [[spoiler:When Kiritsugu first finds out about Shirou being heavily injured and Illya being extremely distraught, he immedietely goes to interrogate Kirei. Kirei truthfully tells him that he had nothing to do with this whole situation, but he can't resist mocking Kiritsugu over the circumstances regardless]].

* SpottingTheThread: Kiritsugu immedietely realizes that [[spoiler:he was the Assassin that Shirou fought when he starts describing the fight]]. His response is to [[spoiler:pull his gun out as proof]]. Shirou takes it surprisingly well, but he internally he wonders what ''exactly'' Kiritsugu did [[spoiler:to become an Assassin class card.]]

** [[spoiler:The battle afainst Artoria Alter goes down a very similar route. Ruby even points out that she's as bad as Archer.]]

* TheDreaded: Kiritsugu built such a reputation as a MageKiller that even the Kaleidosticks are familiar with his methods. [[spoiler:Waver, who saw him kill Tokiomi]], has actual nightmares about him.

* ShipSinking: Much like the source material, both Luvia & Rin have a crush on Shirou, but [[spoiler: both girls keeping secrets from him ended up straining their relationship]]. It's more downplayed and invoked with Gray and she even tried to actively shut down her interactions with Shirou, but if [[spoiler: him admiring Gray while she was fighting Saber Alter]] was anything to go by, it hasn't sunken completely yet.

* DramaticIrony: None of the characters know about the identities of the Heroic Spirits in the class cards - most prominently, nobody has figured out that Shirou's Saber card is Senji Muramasa.
* DrivesLikeCrazy: True to form, Irisviel. By Shirou's naration, Kiritsugu struggles to drive in a legal manner, but he's far better choice than being subjected to Iri's driving and he'd pick Kiritsugu over her any time.

** Unlike canon ''Prisma Illya'', Irisviel and Kiritsugu are unaware of Illya and Shirou's activities. At first.

** Between Shirou and Kiritsugu, they manage to figure out [[spoiler:the identity of the Assassin card, but they keep it between themselves.]]

** The Assassin card is an alternate version of Kiritsugu. [[spoiler:Shirou and Kiritsugu figure it out when the former starts recounting their battle to the later, including a description of his trademark gun and Origin Bullets.]]

* ShipTease: Shirou has shades of this with Gray, as they were able to hit it off quickly enough when fighting Assassin. Some of their later interactions involve the former feeling awkward around her and Gray easily blushing around him, with Add adding fuel to the fire by teasing her. Even in an AlternateUniverse, Shirou’s ChickMagnet tendencies ''still'' kick in.

** [[spoiler:Fou]] is occasionally spotted by the characters spying on them during emotionally charged moments. It's currently unlcear if it's [[spoiler:the version from ''VideoGame/FateGrandOrder'' or the one mentioned in the ''VisualNovel/Tsukihime'' continuity.]]

* MyGodWhatHaveIDone: [[spoiler:Ron's reaction upon realizing that she basically treated Illya like her slave once the Kaleidosticks switched control.]]

* StarterVillain: The first thing that happens to Shirou after he obtains Muramasa's card is get into a fight with Diarmuid Ua Duibhne. He almost gets killed in that fight, and later he shows PTSD symptoms when reminded of it. This is also what motivates Shirou to start hunting the other class cards - he didn't want anyone else to get caught by them.

* TookALevelInKindness: Rin and Lucia become much more considerate of other people's feelings and circumstances after [[spoiler:Shirou turns against them for keeping secrets involving his sister. They come to explain themselves to the Emiyas in person, never make any demands from them, and do not try to take their class cards either.]]
* TroublingUnchildlikeBehavior: Miyu, despite being barely older than ten years old, always acts cold and robotic, never protesting and never questioning order, focused entirely on the class cards. It's not like she cannot feel emotion; she just contains it. Other characters ponder on it but they're generally too distracted by whichever class card they're fighting or [[spoiler:the entire Emiya family drama]].

** [[spoiler:Shirou shows up just in time to help Grey fight Assassin Kiritsugu, even though they both struggle against him.]]

* {{Crossover}}: Between ''Prisma Illya'' and ''Case Files'' - both of whom happen to belong in the same franchise.

* DaddyHadAGoodReasonForAbandoningYou: Kiritsugu admits that he wanted Shirou and Illya to grow up as far away from the world of Magecraft as possible, which is why he and Idk are almost always away hunting down their enemies. He admits he did not think or realize how much their absence would damage their children.

** Shirou's status as an actually OrdinaryHighSchoolStudent - that is, no trauma, no real underlying mental issues, no suspicion that something supernatural is happening, nothing - means that he's extremely poorly prepared for the world of magecraft. His encounter with Diarmuid leaves him traumatized, and so do all the Class Cards except for his Saber card. He judges all magecraft based on that experience and it hits him even harder when he finds out that [[spoiler:everyone he cares about was secretly involved in the world of magecraft all along and kept him LockedOutOfTheLoop]]. Overall, he was absolutely NOT prepared for combat of any kind and he ends up with both mental and physical issues because of it.

* DrivesLikeCrazy: True to form, Irisviel. By Shirou's naration, Kiritsugu struggles to drive in a legal manner, but he's far better than being subjected to Iri's driving and he'd pick Kiritsugu over her any time.

** Even Rin and Luvia are willing to work with each other when under life-or-death circumstances or otherwise equally dire circumstances. Especially once [[spoiler:Shirou's involvement made them realize how badly they screwed up]].

* FlashSideways: [[spoiler:The second he comes in contact with Emiya Alter, Shirou starts getting flashes and then full-blown memories of Emiya Alter's endless killing. Especially the incident where he killed Kiara Sessyoin. It also goes the other way when Shirou manages to beat him, as Emiya Alter suddenly sees part of Shirou's memory of Illya.]]

* GottaCatchThemAll: Everyone except Shirou - and Gray when under pressure - has this mindset regarding the class cards, to the point that [[spoiler:Rin is seriously considering using Shirou's emotional breakdown as a distraction to take the Saber card from him]]. However, since Shirou has no such qualms, and Gray when fighting operates solely on survival instinct, [[spoiler:the Medea card and the Emiya Alter card both end up destroyed]].

** [[spoiler:One of Grey's greatest fears is losing herself completely to Artoria. This actually does happen when she finally faces Saber Alter, as she realizes she needs to lose more and more of herself to keep up.]]

** Unlike canon Prisma Illya, Irisviel and Kiritsugu are unaware of Illya and Shirou's activities. At first.
** The identity of the [[spoiler:black Archer card]] is one of Shirou's most closely guarded secrets. He barely admits it to himself. That said, Miyu ''also'' knows that card and keeps its identity a secret for her own reasons, so we have two people who don't know the other knows.

* MirrorMatch: [[spoiler:The Grey vs. Saber Alter match turns into this, as Grey loses more and more of herself over the course of the fight to the point that she emmulates Saber's style perfectly.]]

* SpottingTheThread: Kiritsugu immedietely realizes that [[spoiler:he was the Assassin that Shirou fought when he starts describing the fight]]. His response is to [[spoiler:pull his gun out as proof]]. Shirou is surprisingly accepting of this.