Heaven's Feel has a great and emotional character arc for Sakura Matou, but her fate isn't as bright in the other two routes. She doesn't appear much and is never freed from Zouken, who continues to torment her, and I wanted to write an alternative happier resolution for Sakura. In Fate route, she becomes friends with Illya at the end, Shirou even notes that she's able to make Sakura smile, something only he could regularly do before. Perhaps she will be the one to help Sakura. I really enjoy both of those characters and thought it would make for an interesting fic. Also, I am ignoring some of the events mention in hollow ataraxia, such as Souichirou and Assassin being killed off by Gil, this fic only follows Fate/Stay Night and Fate route specifically.

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"No, you're lying! I…I don't believe you!"

"Then why didn't he come here to take you even with how much time has passed? You know Kiritsugu, he would've found a way if he wanted."

"He…There must be some reason he wouldn't just leave me! Never! He…"

"Stop denying the obvious, Illyasviel; your father abandoned you. It was difficult for us to believe as well, yet we've seen it with our own eyes. He betrayed von Einzberns, and he betrayed you. Now, he's living his life in peace with a son."

"A son?"

"Yes, Illyasviel. His name is Shirou Emiya, and he is the one Kiritsugu lives for now."

Shirou Emiya. The name that stuck with her for years. Her sworn enemy. The one who took her life away.

Her 'brother'.

…

Sakura was no stranger to long and agonizing nights. She knew how it felt to have worms crawl around her for hours without end, poisoning her skin and blood, enhancing those that wriggled within her. She got used to pain, and at some point, it didn't even hurt anymore. Or at least she convinced herself that it didn't. That those horrifying nights were natural, were simply a part of life for her.

This night was different, even though she had no training to go through. No, this night included a fear very different from the kind she was taught to accept, fear for another. The moment Sakura realized Shirou was a master, her heart sank into the deepest pit of despair. He was her only respite, the one who was unaware of the Holy Grail War and lived a happy life of blissful ignorance, the one who could share this blissful ignorance with her, could make her smile for the first time in years. Now, he was a part of this cruel, merciless world.

She wanted no part in this war, even when the Grail itself chose her. Sakura couldn't imagine facing Shirou in battle. The thought was too much to bear. She gave her servant to her brother, Shinji, who was delighted to use her…Until neither Shinji nor Rider returned home. No one in town knew the real reason for his death, but Sakura understood that the war took him. The war she allowed him to participate in, the war that was never his…It was her fault.

And now, Shirou was in the same mortal danger. Tonight was when the Grail finally materialized, and the war was about to end. Shirou was the last one standing, the one who would have to endure the darkness of the Grail. Sakura was powerless to do anything; she didn't even warn him in fear of revealing the truth about her family. She couldn't do anything, but she couldn't sleep either. Instead, the girl sat in the living room of the Matou Manor, taking a spot on the corner in the sofa and looking down at the floor. Sakura didn't want to look up and stare into his eyes…The head of the house was in the room with her, looking out the window, focusing on the crimson cloud far in the distance. Ever since the war began, Zouken monitored it closely, but now everything was clear. Only Shirou and Saber remained, and theirs was the task to claim their prize.

"Grandfather…" Sakura said quietly and meekly, her voice barely reaching Zouken. The old man turned around and looked at Sakura with his empty yet stern eyes. Even simple movements felt unnatural, revealing the decrepit state of his body, yet it was the stare that terrified Sakura the most.

"What do you want?" He said carelessly. They hadn't spoken since the war began; both were too busy with their affairs, and Zouken wasn't enthusiastic to talk.

"Do you know…Do you know who killed Nii-san?" This was the most Sakura could ask. Her brother wasn't kind to her those last years. But he wasn't a bad person at his core. He was just hurt because of how Grandfather treated him.

"No," Zouken said and turned back to the window as if displaying annoyance at the triviality of Sakura's questions. She didn't expect him to say anything else, but Zouken continued. "But whoever it was, they did us a favor. Shinji was a pompous fool without any strength or talent, a parasite. Giving him a chance was a pointless idea. He stood no chance of winning the war."

A parasite…Bold words from their grandfather. To call someone a parasite when he himself was…Sakura felt worms wriggling inside her, making her entire body feel tense and uneasy. She shouldn't have those defiant thoughts, shouldn't disobey grandfather…

"He was on the hunt for Emiya." Zouken wondered. "It could've been him."

"Shirou wouldn't," Sakura said with more confidence than she could usually muster.

"This War changes people; don't be an idiot and accept it."

"What do you think will happen to him now? There's no one left to fight, right? Just the Grail…"

"I've seen what even a lesser grail can do with my own eyes." Zouken said somberly. "Today will be no different." A faint smile emerged on the old man's face. "I'm curious to see whether he can survive this night."

Sakura would cling to hope until the very last moment. She would've prayed for Shirou…But if the divine forces were like the grail grandfather described, they were not worth praying to. After all, it has been ten years, and still…No one came to save her.

…

This was the end.

The moment her entire life led towards the reason she was conceived.

They become the vessel of the Grail's might.

Once its power began to course through her, Illya lost reality's touch. She was no longer a separate entity, she was filled with its boundless energy, its merciless touch. She was merging with the very darkness that her father sought to uncover ten years ago, defying it and making her pay for his sins.

Illya wasn't awake when she was taken hostage, yet she could hear the echoes that emerged in her memory as she was chained at the epicenter of the summoning. The priest broke into Emiya's house and took her. He fought Rin, inflicted a mortal wound upon her, and left to die. He was her caretaker, yet felt no hesitation at all…

"It's time, Illyasviel. Today, you will fulfill your purpose."

She could no not anything to stop or resist Kotomine, she has become a tool at his disposal, the vessel for the Grail. For a moment, Illya felt that this would be her end, but then she sensed his presence…

Shirou Emiya.

The 'brother' that she tried to kill multiple times, the one who she tried to make her own, the one she used to spite her dead father.

He was here to risk his life, to take on his most dangerous task yet, all to rescue her from jaws of agony and death. Even after all the petty behavior, Illya threw his way after all the times she endangered him and his friends…He came to save her. She knew it was not just to stop the Grail; his dedication and care were clear to her. Now, Illya had no doubt that she was wrong about him. She felt Shirou and Kirei battling at the heart of the Grail, as well as the priest's vile words.

"To be honest, I had hopes for you, Emiya Shirou. I felt that it must have been fate when Rin came to the church with you. You cannot know how happy I was when I found out you were Kiritsugu's son and that you were like him on the inside as well. The wish that did not come true ten years ago…I never expected that I would be able to get my revenge on Emiya Kiritsugu."

That was all Kotomine cared for, to unleash his petty revenge upon Kiritsugu by breaking his son, not unlike Illya during this war. She didn't want to become like this, but after all the pain, manipulation and torment she endured, she simply laughed at the pain, hers or anyone else's.

It wasn't always like this…There were memories of better days buried within Illya's mind, the days when she smiled at her father, eagerly rushing into his arms. She remembered the two of them playing in the snow, laughing as if there was nothing to fear or worry about.

"He betrayed all of us. He betrayed you."

Illya heard those hurtful words many times during the years von Einzberns experimented on her. They chained her in their gruesome laboratory, tormenting her, trying to make her into a perfect vessel and a perfect participant. One trial after another, all for a slim chance to see the light of day, even if it would only be to fulfill her purpose. So much misguided anger and pain, all towards a boy who never knew of what his father did. Even when his allies showed nothing but scorn towards Illya, he extended his hand to her. It was almost the same today…Shirou did not extend a hand.

He extended a sword.

A sword that broke her chains and pierced the priest's vile, rotten heart. Emiya stood victorious.

"I see…There was indeed a time when I gave it to some girl on a whim. I believe it was ten years ago." The priest spoke faintly. "No wonder…I've become weak."

With his death, the nightmare was over. Now, it was the Grail that fell at Shirou and Saber's mercy. Illya wasn't sure what happened, but she felt freedom. Freedom from the shadow that swallowed her, at long last.

"Come on, Illya. Let's go home."