A Crossover Fanfiction of Rin, Shirou, Saber and Astaroth in DxD Universe

In this crossover, Shirou's projection magic could be incorporated by having him project not only weapons but also magical items from the DxD universe. This would show his adaptability. Rin could combine her magic with the devil - related magics in DxD, creating new spells. Saber's noble phantasm could be the key to solving certain major problems in the DxD world, like a powerful threat that even the devils can't handle. Astaroth's powers could be used to test the limits of the Fate characters' abilities, forcing them to grow and develop new strategies to deal with him.

Saber could fit in as a powerful ally. Her noble phantasms and combat abilities would make her a force to be reckoned with. In a world full of supernatural beings like Highschool DxD, she would be another strong addition. She might be seen as a sort of mysterious figure that both the devils and the angels would be curious about.

One possible scenario in such a fanfiction could be Shirou Emiya's unique abilities from the Fate series being introduced into the Highschool DxD universe. His projection magic might cause quite a stir among the devils, angels, and fallen angels in that world.

Saber is often a symbol of honor and power, and in relation to Rin, they can be written in fanfiction as two characters who grow to understand and respect each other more. Rin's knowledge of magic can be a key factor in their interactions. However, when it comes to lemon fanfiction, it's not a proper area to explore their true characters as it usually involves vulgar content.

One way the fanfiction expands on the characters is through their interaction with new elements. Shirou, who was mainly dealing with his own world's magic system, now has to deal with Saber's different magical heritage. This forces him to adapt and learn, showing his intellectual side more. Saber, being from a different time and place, in a crossover might have to face modern - day ethics and values. This challenges her traditional beliefs and shows how she can either hold on to them or evolve. Their relationship in the crossover also allows for exploring their mutual respect and how they can support each other in ways that were not as evident in the original story.

One popular 'Saber x Rin x Shirou' fanfic is 'The Three's Bond'. It beautifully weaves their relationships together in an alternate universe setting. The story shows how they support each other through various challenges.

The idea of sacrifice also pops up a lot. Given the nature of the Fate series, the characters may be in situations where they have to sacrifice for one another. In fanfics, this can be explored in different ways, like Saber sacrificing her power to protect Rin and Shirou.

Well, a great storyline might involve Shirou and Saber swapping roles in some way. For example, Saber having to take on Shirou's daily life tasks, like going to school or doing mundane jobs, while Shirou has to lead in battles like Saber usually does. This role - reversal can bring out a lot of comical and also deep character - development moments. Also, a plot where they are in a parallel universe where their fates were different from the original story and they have to come to terms with these new versions of themselves.

In fanfiction, Shirou and Saber's love is often depicted as a complex and beautiful relationship. It's a love that transcends their different natures. Shirou, with his strong sense of justice, is drawn to Saber's noble and powerful presence. Their love story can be full of moments of understanding and mutual growth.

To create an engaging OC for a Highschool DxD Astaroth fanfiction, think about their goals. Are they seeking power, revenge, or something else? This will drive their actions in the story. Also, consider their relationships. How do they view Astaroth at the start? Do they fear, respect, or love him? Their initial attitude can change over the course of the fanfiction, creating a character arc. And don't forget about their skills. If they have a special power or ability, it should be something that ties into the overall plot and their interactions with Astaroth.