I owe someone a fic idea and I don't remember who or why, but I'm doing it now.
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Rin Tohsaka hated losing.
She rarely hated anything, thought hate was beneath her elegant persona. Instead, she settled on merely having an intense dislike for things. She intensly disliked the London weather: wet, dreary, grey and unendingly blah. She disliked her roommate; a blond balloon breasted bimbo bitch who flaunted her unearned money like some scumbag Yakuza member. She disliked most of her courses at the Clock Tower; the whole place felt like a daycare for sociopathic rich kids. The one course she enjoyed, she had a deep dislike of the teacher: a racist jerk with girly hair who stunk of cigars and ressentiment. The fact he survived a Grail War didn't make him special; even Shirou survived a Grail War, and he was an idiot.
It was that damn El-Melloi's fault she was in this situation anyway, losing over and over with no comprehension or reprieve. These tools were unfamiliar, these visions were maddening, these actions were increasingly futile. And to make matters worse...
"Ha! In your face, Tohsaka! I am an unstoppable loli killing machine!"
...She was getting embarrassed by the damn Einzbern kid. Who was now jumping onto the kotatsu, arms outstretched to curry the favor of the crowd. A crowd comprised of Saber, Rider and Sakura. She didn't care as much about looking bad in front of the Servants, but Sakura was her little sister, dammit; she had to look cool in front of her! Rin was just glad Shirou was in the kitchen doing Shirou things. She didn't think she could live with the shame of him seeing her like this.
She stared at the damnable...controller, Shirou called it? Funny name, since it didn't seem to control her character at all like she wanted. Even after Shirou taught her what the buttons and joysticks (that brought no joy) did, the stupid thing still didn't work right.
She threw the controller down in a huff and pointed an accusatory finger at Illya. "You're obviously cheating with your wicked demon loli powers!"
Illya just smirked at her. "No Johns, Tohsaka."
"Who is John? What does he have to do with this dumb fighting game?"
"Nee-san, I think she means don't make excuses," Sakura says, sipping tea.
"Accepting victory or defeat with honor is an integral part of combat," Saber says knowingly to deaf ears.
"I'm not making excuses! She's unconsciously using Einzbern Wishcraft or something, because nothing I do works!" Rin stamped her feet, clearly upset. She felt her face get red, which only incensed her further.
"That's because you're free, Tohsaka," Illya says with a mocking lilt, "F-R-E-E."
"Are you calling me a prostitute, you defective little brat?"
Illya's eye twitched; her Command Spell - cum Crest flared an angry red for a moment. "Call me defective again and I'll show you what Einzbern Wishcraft looks like."
Saber had summoned her armor, Sakura's Mystic Code crept up her arm like an infection. They were ready to step in, given the very likely chance this came to blows. Rider was drinking Irish Tea, so she didn't really care what happened. A tense, breathless moment passed, until Shirou came out with fresh made onigiri.
"Ah, Illya, Tohsaka; are you enjoying Melty Blood?"
They both train their eyes on him; tension deflating with his easy smile and their growling bellies.
Illya, predictably, turned into a brother-seeking missile at the sight of her onii-otouto. She latches onto his neck like a lamprey, beaming so hard she actually gives off light. "Onii-chaaaaaan! I beat the Tohsaka girl 21 times in a row! I deserve a prize!"
Shirou pats Illya on the head. "Good job! You have been helping her learn the game, right?"
It took one look at Rin's furious, embarrassed face to put the lie to that idea. He instinctively swings Illya to his back so his arms would be free and he could put himself between the two of them.
"Er, beating her mercilessly until she cries or stops being a scrub is helping, right?" Illya says without a hint of guile or empathy.
"Illya..."
"Don't use the Dad Voice on me, Shirou." Illya pouts, "I'm the eldest sibling."
Shirou smiles smartly. "So you shouldn't call me onii-chan, then."
"Geez, Shirou! That's unfair, unfair, super unfair!" Illya kicks on Shirou's back.
"The only thing unfair here is Illya," Rin grumbles.
"You mad?" Illya sticks her tongue out at Rin from over Shirou's shoulder. Shirou shifts in case Rin decides to take a swing.
"Stop it, Illya," says Shirou, "or you lose your onii-chan privileges and you get one fewer onigiri."
"You wouldn't dare," Illya hisses, shocked at this sudden betrayal.
"I would and I will, if you don't stop teasing Tohsaka."
Illya disembarks from Shirou's back to sit on the floor, arms and legs crossed and cheeks puffed in righteous indignation. Rin soon follows, sitting across the kotatsu from Illya. Sighing, Shirou lays out the onigiri and takes a seat next to Rin.
"That bad, huh?" He asks. Rin nods, lips pursed into a thin line.
He rubs her shoulders. "We can have some special sessions later, okay?" There's a chill in the air; Shirou sees red marks on Sakura's face and a long shadow behind her. "Not like that! I'm just going to teach her basic combos and footsies!"
"I'm sure you'd love to play footsies with Nee-san, Senpai..."
Rider takes this time to look up from her book and her booze to give Sakura a knowing glance.
The air grows warm, the red marks go dim and Sakura's shadow recedes. "S...Sorry Senpai, I lost myself for a little bit." A new redness blooms on her cheeks.
Illya pouts while eating her onigiri, which is both impressive and cute. "How come Tohsaka gets to spend alone time with Onii-chan?"
"Because Shirou isn't into little girls," Rin says, looking to hit below the belt.
"I'm older than you as a Magus and as a woman, Tohsaka."
"Not like you act it," Rin snipes.
"Tohsaka..." Shirou uses the same stern voice on Rin he did Illya.
"She started it," Rin sulks, biting into her onigiri.
"Look, how about we play a nice party game after this? Like Mario Kart or something?"
Rider perks up. "Is that a racing game?" Shirou nods. "I wouldn't mind playing that, then."
"I'll play anything Onii-chan wants to, especially if it's bedroom play!" Illya hugs Shirou's arm for emphasis, drawing the judgemental stares of the other girls and a nervous chuckle from Shirou.
"Word choice, Illya..."
"What do you mean, word choice? I want you to pound my loli pus-"
Shirou bolts from the table, bowling Illya over. "HA HA OKAY LET ME GO GET MY GAMECUBE WITH MARIO KART."
With Shirou gone, the eyes of judgement fall on Illya.
Rin is the first to speak. "You are a disgusting little thing, you know that?"
"Hey, everybody else here got a turn," Illya frowns, brushing hair from her face. "And he certainly didn't mind me tying him up and straddling him." The frown turns into a lascivious Cheshire Cat grin.
The table is stunned into silence again, any comeback dying in acrimonious disgust. Once again, they are saved by Shirou, GameCube and controllers in hand.
***
"Ha! I am the greatest of all time! Bow down and pay homAAAAAAAAH!"
The GameCube explodes in a stream of curses as Rin does the same. Normally a Gandr shot didn't require the user to curse with it, but this was a special occasion.
Rin Tohsaka really hated losing.