One common theme is the clash of different moral codes. Kiritsugu has his own set of beliefs, and when he is crossed over into other worlds, like a world of superheroes or a magical realm, his way of thinking often clashes with the local characters. For example, in a crossover with a world of knights, his willingness to use underhanded tactics for the greater good might be at odds with the knights' chivalry.
One great kiritsugu emiya crossover fanfiction is 'Kiritsugu in the World of Harry Potter'. It imagines Kiritsugu being summoned to the wizarding world. His skills and unique moral code create really interesting interactions with the characters there. Another one could be 'Kiritsugu and the Avengers Crossover'. Here, he teams up with the Avengers and his strategic mind helps them in battles in a very different way compared to their usual approach.
In such a fanfic, it could focus on the battles they fight together. With Archer's long - range capabilities, Emiya's versatility, and Saber's powerful swordsmanship, they could be an unbeatable team. Kiritsugu might be the strategist behind their every move. The story could also delve into their pasts. Saber's past as a king, Archer's as a hero, and how those pasts influence their actions in the present. It could be a really exciting story full of action and drama.
It could develop Archer's character by showing his internal conflict. He might be reluctant to follow Kiritsugu's orders at first, but as he sees the bigger picture, he starts to cooperate more. For Saber, it could show her growth from a somewhat rigid king to someone who can adapt to modern times. Emiya's character could be developed through his interactions with the others, perhaps learning new skills or ways of thinking from Archer and Saber.
Another idea is that Kiritsugu summons Shirou because he foresees a future threat that only Shirou can prevent. This could involve time - traveling elements. Shirou might have to go back in time to change certain events. During this process, he and Kiritsugu would have to work together to figure out how to manipulate time without causing major disruptions.
One common theme is redemption. Given Kiritsugu's complex past, many fanfics explore his journey towards redeeming himself in the context of the Beast Lair.
In an 'emiya meets emiya assassin fanfiction', it could start with Emiya Assassin being sent to assassinate someone that Emiya is protecting. They cross paths and a tense confrontation ensues. However, as they face off, they both sense a strange connection. Instead of immediately resuming the fight, they take a moment to talk. Emiya Assassin reveals his reasons for the assassination, which are more complex than Emiya initially thought. They then find a middle ground and decide to work together to expose the real mastermind behind the plot to kill the person Emiya was protecting, all while exploring their own identities as two versions of the same individual.
Well, in such a fanfic, Kiritsugu might summon Shirou for a crucial mission. Maybe there's a powerful enemy that only Shirou can defeat with his unique abilities. It could also be that Kiritsugu summons Shirou to pass on some important knowledge or skills. Or perhaps it's a situation where Shirou is the key to saving a particular world or timeline that Kiritsugu is involved in.
Archer is often well - written in these fanfictions. His complex personality and his own set of values can create a lot of interesting interactions, especially when paired with Kiritsugu.
One possible plotline could be Archer and Kiritsugu teaming up to face a powerful common enemy. They might combine their different skills and strategies to overcome challenges.