Prompt: "shirou summons MHX... but the holy grail war is literally just artorias. swimsuits! alternate class containers! bunnygirl costumes! alters! alternate universes! lostbelts! of course, it's quite obvious who would be summoned as the saber of the war... unless? not all servants should appear directly, it's fine if they're only referenced." — Tara, answered by Exstarsis
The Real Saber, Definitely (or, as everybody called her behind her back, 'Assassin') ghosted around the edge of the Homurahara High club building. The bunny-suited Ruler (she definitely had to die) had delivered an invitation for The Real Saber to be here at this hour. Of course she'd rejected it. But when she'd followed the Ruler after (she was so oblivious!) she'd realized the Ruler had delivered invitations to every other Servant as well.
The opportunity was too good to pass up. She snuck into the building and tip-toed down the hall, toward the sound of raised feminine voices. When she rounded the corner, she was so distracted with thoughts of how to destroy all of them at once, she ran right into a broad, non-squishy chest.
"Whoa!" said the Fake Saber, catching her as she almost fell. "Be careful, my lady."
The Real Saber leapt backward, reaching for her Excalibur automatically. Fake Saber gave her a wry grin and held up his hands. "I suppose you've come for the party, too?"
The Real Saber hesitated and then let her weapon vanish. Fake Saber's only crime was claiming to be a Saber, and that put him below everybody else in this damn war on her hit list. He'd definitely go down eventually, but now was not the time. Not when she could get information out of him.
"Hah! Why aren't you in there?" she demanded. The door behind which all the women wearing her face laughed was clearly visible.
Fake Saber flushed a little. "Ah, well. They… It didn't seem right for me to be joining them." When The Real Saber glared at him suspiciously, he waved a hand at the door. "You're an Assa—uh, why don't you go and see for yourself?"
Keeping her eyes on the tall man, The Real Saber edged past him until she was near the door. Then she carefully peeked inside.
Six women sat around several tables pushed together. There was the bunny-suited Ruler and the swimsuit-wearing Archer. The Rider with the ridiculous hat. The weird Caster. The milk-obsessed Lancer who normally wore black, and even the Berserker who sometimes triggered the strangest feelings in The Real Saber.
And none none none of them were wearing all of their costumes, but all of them were holding cards. The Archer, who sat in profile, had lost her top and one of her shoes (but retained her jacket). The Lancer had lost a lot more than that, and most of it was piled beside the Archer. The Ruler mostly wore flimsy transparent veils. The Caster had clearly focused on keeping her tunic, which covered the essentials, but she'd lost everything else and she was laughing about it. And Berserker—
Berserker raised her gaze from her cards, still mostly clothed, and met The Real Saber's eyes for just an instant before The Real Saber squeaked and ducked away, covering her face.
When she looked up, Fake Saber was looking down at her in sympathy. "Is Rider still winning? They were happy to let me step out once Archer lost a hand."
"Why are they doing this?" demanded The Real Saber, waiting with her heart in her throat for Berserker to fling open the door and drag her in.
"Uh. I think they said that since they were all variations on the same person, it didn't make sense for them to kill each other. If one won, they all won. So they wanted to have fun?"
"Who suggested it? Ruler?" The Real Saber clutched her hair, calming down as the door remained closed.
"I think it was Archer, actually." Fake Saber got a thoughtful look on his face. "She lost the first few hands. I'm surprised she hasn't been knocked out yet."
The Real Saber, Definitely thought of all the armor piled next to the Archer, and casino Ruler on the other side of the table. Her nose itched like it always itched when there was a cheating lookalike around. Then she thought of Berserker, still mostly clothed, and grew thoughtful.
"Are you going in?" asked the Fake Saber.
"They're totally wrong about how if one of us wins we all win, you know."
"Oh?" he said, with a faint smile.
"Yeah. That awful Archer thinks she's going to win. And I am going to prove her wrong."
With that, The Real Saber marched into the room, ready to do whatever she had to win, including an alliance with her old rival Berserker. And if the thought made her just a little bit happy? Well, who cared about that?