Metal on metal. Magic on magic. Kotomine stalls as much as he can. In one hand, he holds a quartet of Black Keys and holds off Assassin. With the other, he miraculously protects himself from Caster's magecraft. After a minute, Caster resigns and stops firing ether beams.
Assassin's attacks pick up the pace as his body emanates shadows like a human car exhaust tube. Simply put, Assassin's raw strength is higher than Kotomine's, and they are evenly matched in terms of combat skill. Although Assassin burst his energy outward to increase performance, Kotomine has a superior insight and can calmly analyze each strike and combination of attacks, pulling off the correct counters at every turn. A standstill.
Kotomine breaks off and hops back. His feet crossed ten meters in a second. Sha Naqbua Imuru feeds you with his intent – to throw the Black Keys at Assassin's feet and expand them into a wall, then retreat to a more advantageous position.
Fortunately, that's not required. A barrage of golden lights flash across the alleyway. Assassin barely sees it coming and manages to teleport into Caster's shadow just in time for Caster to raise a blue forcefield to guard them both from your terrible vengeance, the former of which prompts your curiosity.
What really is a shadow, anyway? Isn't everything at night, technically a shadow of the entire planet? Isn't the entire alleyway coated in shadow because the sun can't entirely shine into it? Or is the 'shadow' subjective to Assassin's current position? Maybe he can only teleport into spaces that are darker than the majority of their surroundings? Or maybe all logic is absent and 'shadow' is more conceptual, related more to the idea of 'it has to be darker than a certain threshold.'
Anyway, it doesn't matter. Kotomine's eyes gleam with hope, thinking you came to save him. So do Rin's, as she stands behind you excitedly with clenched fists raised up to her chin and watches the swords explode the cobblestone of the alleyway into dust. Caster lifts his forcefield and watches for any next movements.
You frown with strong lamentation at your loss. Magical, explosive swords. Fifteen. From your own treasury. Had you not been her Servant, you'd have told Rin they're coming out of her paycheck. Not like she can afford them, however, which in your times meant eternal slavery. The picture of having her feeding you grapes returned a smug smile to your face, as you closed your eyes. The enemy misread this, as you disregarding them and underrating their ability to fight.
Assassin and Caster give you hostile glares, a fact you can read even through Assassin's hood, but you spare these nonsensical, impertinent children no interest. Everyone prepares to resume the fight, adjusting their tactics to mathematically accommodate your presence and support. Kotomine looks ready to receive your ranged support.
To their surprise, you turn away. "Welp, I contributed." Nonchalantly, you walk away. Rin's jaw falls and the surprised, half-turned Kotomine feels a dagger stabbing into his back –– both a metaphorical and literal one, as Assassin had already crossed the distance the moment he saw the opportunity to attack the confused, Fake Ruler.
Kotomine kicks him in the stomach, throwing him back, then the fight resumes without your interference.
Rin looks at you, then at the fight, then back at you. "Eh? Caster, we can't leave them!"
"That's where you're wrong, Rin. That is what I am doing right now," you state with dry, cold pride and veiling a smug grin, the image of her feeding you grapes still stuck in your head and almost making you crack up with snobby laughter.
"B-But..." she wants to say something, but thinks better on it and closes her mouth. At least for three seconds, before she suddenly states: "But war!"
[] "Just this once." You'll feed her egotistical desires this one time, because you can't help but want to kick that other Caster's bottom parts.
[] "Okay, but then you feed me grapes." Equivalent exchange, as they say. And what better exchange than having your Master feed you sweet goodness?
[] "Let's let Kotomine deal with the suitors." Clearly, they are competing for your attention. But to fight the King of Heroes, you must first prove worthy. Allow Kotomine Shirou to deal with the paperwork. If one of them beats him, they'll be your target later, if you care enough about fighting them.
[] "So what's this McDonalds thing I heard about?" Who really cares about this situation?
[] Write-in.