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.
In a fanfic where Kiritsugu is summoned in the 5th Grail War, he would bring his own set of skills and motives. His skills as an assassin would come in handy. He might try to figure out the true nature of the Grail this time around, especially after his experiences in the previous wars. His relationship with other Servants could be complex. Some might respect him for his past achievements, while others might see him as a threat. And his actions would likely be guided by his own moral code, which, although not entirely conventional, has its own logic.
His abilities would be a game - changer. His strategic mind could outwit many of the other Masters. His use of modern weapons combined with his Servant's powers would be a deadly combination.
His character might become more confident. With unlimited mana, he'd be able to face challenges without hesitation. He'd no longer have to hold back due to mana constraints.
In Shirou Reality Marble fanfiction, his character development can be influenced by how others interact with his Reality Marble. If other characters are able to break through his defenses within the Marble, it can force him to re - evaluate his relationships and his own self - worth. This can cause him to become more open - minded and less self - sacrificing as he realizes the value of his own existence apart from his ideals.
His projection magic might be affected by the different magical rules in the Highschool DxD world. Maybe it becomes more powerful or has some new limitations. For example, projecting holy swords could have a different energy cost or be more effective against certain types of devils or fallen angels.
In the original, Shirou might have certain limitations and a set personality. But when reincarnated as a gamer, he could become more confident. For example, he might be more willing to take risks in battles or interactions because he has the knowledge and abilities from the gaming world. He could also be more strategic as he has learned different tactics through gaming.
One possible fanfic could involve Shirou using some kind of magic or special ability to summon Naruto. Maybe Shirou is in a difficult battle and needs Naruto's strength. Naruto could arrive with his signature orange jumpsuit and start using his shadow clone jutsu to turn the tide of the battle. It would be an exciting crossover of the Fate and Naruto universes.
Overall, their relationship in fanfiction is often explored in different ways. It can range from a brother - sister - like bond to a more romantic relationship. The fanfic authors play with their personalities and backstories to create unique and engaging stories. For instance, some fics might explore how their different upbringings affect their relationship, with Shirou's more normal upbringing contrasting with Illya's complex magical heritage.