"King of Heroes, Do You Have Enough Cards?" by Mereo Flere
Saw a challenge on Beast's Lair, wrote for it, got this, and Kyokushi gave me the title.
Of all of the Holy Grail Wars he had been summoned to, this had to be the most ridiculous - and he knew for a fact that he had once been summoned to the Moon. He even suspected that the Tohsaka Rin there even knew how to use technology, though even he thought that might have been a little too crazy.
Not as crazy as this, however. He never would have imagined that there was an alternate reality out there where the Holy Grail had been corrupted by something other than Angra Mainyu. It was something that he had taken for granted, really; a familiar evil was easier to handle than one you didn't know, after all. This, though... while he couldn't really call it evil, he still wondered what had possessed the Einzbern to summon something like "The King of Games." What, did they think that it would check mate its opponents to death?
Regardless of their intentions for that spirit, the fact of the matter was that it had lost early on in the war, just like Avenger had. And, just like Avenger, the spirit's presence in the Grail twisted it, ultimately changing the wars that followed. Rather than acting as the vessel of All the World's Evil, however, the rules for the war simply changed. No longer did servants duke it out directly with their noble phantasms, as it had been in Archer's lifetime. Instead, the battle took a different form, a different medium: Card games.
Goddamn card games.
He couldn't believe it at first. Even when Rin told him that's how the war was fought, he was sure that she had made a mistake. She did that, after all, make mistakes. It ran in her family after all; sometimes, it was simple stuff like forgetting about Daylight Savings Time. Other times, there were more drastic consequences, like giving your daughter to Zouken. Hell, both Tokiomi and Rin had made the mistake of trusting Kotomine, and only one of them managed to (barely) live through that. Believing, for some strange reason, that the war would be fought with pieces of cardboard wasn't that unusual for them.
When Lancer showed up, however, doing his usual reconnaissance thing for Kotomine, and challenged him to a game of duel monsters... well, Archer was forced to believe. It wasn't that Lancer was any more convincing than Rin, however; it's just that when Archer tried to trace his swords all he managed to do was summon up a pair of equipment cards named after his blades.
They weren't even that good. 500 Attack Point increase each? That was just insulting.
In the end, however... Archer couldn't really complain. As it turned out, having heroic spirits from the past duke it out in a card game wasn't a great idea. Berserker didn't even know how to play the game, so he went down easy. Caster depended too heavily on spell and trap cards, so a combination of Royal Decree and Silent Swordsman Level 7 was all it took to defeat her. Assassin was taken out when Caster was defeated, while Rider had been defeated by Saber.
As for Saber herself - her deck wasn't all that good, to be honest, but her instinct seemed perfectly suited for a game. Despite lacking an optimized deck, her dragons gave him quite some trouble as she somehow managed to counter his Dragon Capture Jar every time he set one on the field - but in the end his Buster Blader made short work of her Blue Eyes White Dragons. Though she managed to fuse them together into a three headed monster, the power it gained from the polymerization was still nothing compared to thousands of attack points all of the dragons in Saber's graveyard gave to Archer's warrior.
Now, however came the final battle - the last opponent he would have to face before this ridiculous war was over: Gilgamesh.
The King of Heroes had shown himself right after Saber was defeated. Archer expected him to be mad, but instead Gilgamesh had been... amused. Maybe it was because Gilgamesh was no longer interested in someone that had lost to a Faker like Archer. Maybe, in this world, he had decided not to obsess over her. Whatever the reason, though, it was clear that Gilgamesh was interested in him.
Instinctively, Archer moved to dodge when he felt Gilgamesh's presence, but there was no need to. Duel Monsters was not the sort of game you could win with a sudden ambush. As Saber had described it, it was a game of honor - of opponents exchanging blows with each other, and the fight began only when the mutual enemies knew each other was there.
Gilgamesh couldn't stab him in the back, nor did he feel a need to. "You have no pride, Faker," he said, as he stepped into view in front of Archer. "Constantly changing your deck to suit your opponent - even the witch had placed more heart in her cards than you."
Archer shrugged. "I do what it takes to win."
"Perhaps." Gilgamesh laughed, running a hand through his hair as he looked down on Archer down the bridge of his nose. "Against trash like the ones you faced, little tricks might be enough. However, Faker, it's time you took a lesson from a true duelist."
Archer narrowed his eyes, and regretting that he didn't have time to rebuild his deck. However, without any other choice but to fight, he was forced to pull out his cards and start shuffling them. It was only when Gilgamesh pulled out his deck that Archer realized just how much trouble he was in.
"You have got to be kidding me."
"Are you ready Faker? It's time to duel!"
The moment that Archer had seen Gilgamesh's deck, he knew how things would play out. Though he hadn't seen the cards in play yet, he had figured out what Gilgamesh had put in his deck. From the moment the first draws were made, it was simply a matter of time until one of them fell.
"I never thought it would end up like this..."
"Really?" Archer raised a brow as he watched his opponent stumble backwards - thousands upon thousands of cards scattering to the floor as they spilled out from Gilgamesh's duel disk.
"Of course! How could I possibly lose? I had the prototype of every card that ever came into existence!"
"...yes," Archer said with a sigh. "But maybe, just maybe... you know, you shouldn't have put them all into your deck."