History Heartwarming / ChaosTheory

* [[GreenEyedMonster Though Sakura candidly admits to hating Illya]], [[NotSoDifferent she knows ''exactly'' what she's been dealing with]] [[IWantMyBelovedToBeHappy and cares for Shirou]] [[spoiler: enough to go along with Rin's plan to get her a new body and thus a normal human lifespan so she can be with Shirou.]]

* Rin, upon seeing Sakura collapse at school, swiftly decides to take her to the Emiya household, with the justification of monitoring her and the other Matous. [[spoiler/The first of multiple moments she really starts being a sister to her.]]

** Building on this, Archer outright admits to himself in an early chapter that he will not hurt MoralityPet/Illya, even if it’s the easiest way to defeat Berserker [[spoiler: and give him an opening to kill Shirou.]] [[EveryoneHasStandards/There are just some things he will not do.]]
** Later both Shirou and Archer discover [[spoiler: Caster has taken and hurt Illya.]] They both immediately resolve BigBrotherInstinct/to kill Caster for this.

* Though Sakura candidly admits to hating Illya, she knows ''exactly'' what she's been doing with and cares for Shirou [[spoiler: enough to go along with Rin's plan to get her a new body and thus a normal human lifespan so she can be with Shirou.]]

** In Chapter 1: Shirou has just met Illya, and has no idea of who she is, why she gave him a cryptic warning... nothing. Yet despite this - and an instinct '''screaming''' him that approaching her would be risking death - he ''reaches out to her''. He puts on a big-brotherly expression, he offers to walk her home or lend her money for the bus service, he compliments the hair she inherited from her mother... and in the end, the part of Illya that still yearns for affection wins over the ten years of cynicism drilled into her by the Einzberns.

* Unrelated to Shirou and Illya, Saber protecting [[TheWoobie Sakura]] from [[DomesticAbuser Shinji]] is both this and a SugarWiki/MomentOfAwesome.

* Unrelated to Shirou and Illya, Saber protecting [[TheWoobie Sakura]] from [[DomesticAbuser Shinji]] is both this and a MomentOfAwesome.

* Put simply, just about ''every'' interaction between Ilya and Shirou either has or ''is'' one of these.
** In Chapter 1: Shirou has just met Ilya, and has no idea of who she is, why she gave him a cryptic warning... nothing. Yet despite this - and an instinct '''screaming''' him that approaching her would be risking death - he ''reaches out to her''. He puts on a big-brotherly expression, he offers to walk her home or lend her money for the bus service, he compliments the hair she inherited from her mother... and in the end, the part of Ilya that still yearns for affection wins over the ten years of cynicism drilled into her by the Einzberns.
** In Chapter 6, he's out to get supplies for lunch (for ''[[BigEater Saber]]'', among others), and runs into Ilya again. After some small talk, she asks - and then begs - him to give her a tour of the town just to spend time with her. Despite knowing he'll get in trouble if he delays getting back, he cannot resist the urge to make her happy. Following that...well:

* In Chapter 14, [[spoiler:Shirou meets Irisviel. She does not carry any emnity towards him or Kiritsugu for what Ilya went through the last ten years - she simply notes that he's been a miraculous influence on her little girl by giving her the affection she's been starved of, and asks him to do his best to save her. And though Shirou's unsure if he's dreaming or not, he accepts. Whether it's meant to be ShipTease or not, it's beautiful to watch because either way, Iri seems to have accepted Shirou as her own.]]
* Chapter 15: [[spoiler:Despite her misgivings about Ilya, Saber jumps in front of Gilgamesh's attempt to skewer her and blocks the sword he fired from Gate of Babylon. Even better in that she also defended ''Berserker'' (who had leapt in front of Ilya first) from the attack, and declared a no-strings-attached EnemyMine with them, against Gil. Ilya is left stunned, and actually realises that BeingGoodSucks might not ''quite'' be true.]]

* Not long after that, in Chapter 16 we get Ilya's awesome and deeply moving KirkSummation [[spoiler:directed at Gilgamesh]], which also counts almost as a HeelRealisation and a testament to her CharacterDevelopment up until now. Not to mention Saber's response.
--> '''Ilya:'''"That's... wrong."

--> '''Ilya:''' "[[ShutUpHannibal That's wrong]]! If... you love someone, then... then doing anything that makes them sad should make you sad. And making them happy makes you happy. You... if you have to force them to love you back then it's just... it isn't right. They should love you because they love you!"

* In Chapter 23, after Ilya [[spoiler:lost Berserker]], both Shirou ''and'' Saber [[spoiler:pledge to act as her Servants as a form of penance (for Saber being forced to [[MercyKill put down]] the possessed Servant]]. This causes her to blush in embarrassment, evidently moved and flattered by their (admittedly [[IdiotHero stupid]] [[JadeColouredGlasses in her mind]]) HonourBeforeReason.
* After being a massive {{Troll}} towards poor Shirou in Chapter 25, Ilya has a deeply vulnerable moment where she admits to him that although it might not mean nearly as much to him (which it does, but she doesn't know that), the kindness and warmth he's shown her from the start has made her genuinely happy for the first time since her parents left her life; she even remembers how compassionate and loving her father Kiritsugu was, the hate she had build up lifted like a fog thanks to his adopted son. Shirou melts and embraces her as he silently admits, in his mind, that having her in his life does make him happy.

* [[spoiler:Saber Lily is forced to kill Mordred again, but Mordred dies at peace because Saber had renamed her attack "Excalibur Mordred".]]

* To even the odds against Angra Mainyu, [[spoiler:Illya and Sakura perform a mass summoning. Among the Servants who arrive are Medea Lily and Heracles as Archer. Though the two have no memory of their past summoning, Illya and Sakura are very happy to see them again.]]

* In a dark way, [[spoiler:Angra Mainyu summoning corrupted Servants from the character's past, even though they are trying to kill them. Gilgamesh is reunited with Enkidu and Iskander. Rider faces her younger self as well as her sisters Stheno and Euryale, who say they will fight together as a family. Saber faces Lancelot and Mordred.]]

* In a dark way, [[spoiler:Angra Mainyu summoning corrupted Servants from the character's past, even though they are trying to kill them. Gilgamesh is reunited with Enkidu and Iskander. Rider faces her younger self as well as her sisters Stheno and Eurayle, who say they will fight together as a family. Saber faces Lancelot and Mordred.]]

* After Shirou [[spoiler:severs Sakura's connection to the Grail, he shields her from the backlash, holding her tight while saying "it'll be okay" to her.]]

** Archer in his [[spoiler:final moments when Shirou of all people actually cries for him.]] His final thoughts were about how he was glad that [[spoiler:someone actually expressed sorrow for his passing. Something he did not get in life]]. Again, heartbreaking, but sweet.

--> '''Ilya:''' "[[ShutUpHannibal That's wrong]]! If... you love someone, than... then doing anything that makes them sad should make you sad. And making them happy makes you happy. You... if you have to force them to love you back than it's just... it isn't right. They should love you because they love you!"

* Chapter 15: [[spoiler:despite her misgivings about Ilya, Saber jumps in front of Gilgamesh's attempt to skewer her and blocks the sword he fired from Gate of Babylon. Even better in that she also defended ''Berserker'' (who had leapt in front of Ilya first) from the attack, and declared a no-strings-attached EnemyMine with them, against Gil. Ilya is left stunned, and actually realises that BeingGoodSucks might not ''quite'' be true.]]

* After being a massive {{Troll}} towards poor Shirou in Chapter 25, Ilya has a deeply vulnerable moment where she admits to him that although it might not mean nearly as much to him (which it does, but she doesn't know that), the kindness and warmth he's shown her from the start has made her genuinely happy for the first time since her parents left her life; she even remembers how compassionate and loving her father Kiritsugu was, the hate she had build up lifted like a fog thanks to his adopted son. Shirou melts and embraces her as he silently admits, in his mind, that having her in his life does make him happy.

* In Chapter 23, after Ilya [[spoiler:lost Berserker]], both Shirou ''and'' Saber [[spoiler:pledge to act as her Servants as a form of penance (for Saber being forced to [[MercyKill put down]] the possessed Servant]]. This causes her to blush in embarrassment, evidently moved and flattered by their (admittedly [[IdiotHero stupid]] [[JadeColouredGlasses in her mind]]) HonourBeforeReason.

--> '''Saber:''' <smiles warmly> "Well-spoken, Lady Einzbern. [[spoiler:Perhaps choosing to fight by your side was a better decision than I had imagined.]]"

--> '''Saber:''' "[[spoiler:Perhaps Shirou is influencing me oddly, to defend a potential foe so. Or perhaps I am still simply curious as to what you know about the oddities in this War. But this Archer is no ally of mine, Lady Einzbern, and [[IOweYouMyLife I do owe you a debt of assistance]]. If you stand against him, then I stand with you.]]"