Another aspect to consider in this fanfiction is the cultural clash. The feudal - like society in the Naruto world and Arturia's own Arthurian era background. Arturia might find the concept of ninja villages and the way they are structured quite strange. At the same time, Naruto and his friends could be fascinated by Arturia's tales of Camelot and the Round Table.
Well, you could have an Arturia Pendragon crossover with a post - apocalyptic setting. Imagine her leading a group of survivors, using her combat skills and leadership to help them thrive in a desolate world. Or perhaps a crossover with a magical school setting. Arturia could be a visiting instructor, teaching the students about honor and combat.
First, decide on the world or character you want to crossover with Arturia. Then, think about how their two universes can interact. For example, if it's a crossover with a superhero world, consider how Arturia's abilities compare to the superheroes'.
A great idea for this fanfiction would be to explore how Arturia adapts to the ninja world. She would have to learn about chakra and ninjutsu. Maybe she could combine her own magic with chakra to create unique attacks. For example, infusing Excalibur with chakra to make it even more powerful. This would also make for some really cool fight scenes in the story.
The 'arturia pendragon visual novel' is perhaps centered around Arturia Pendragon. It may start with her origin story, how she pulled the sword from the stone. Then it could show her ruling Camelot, dealing with internal and external threats. The visual novel might also focus on her personal growth, her ideals of justice and chivalry, and how she copes with the weight of leadership. It may also introduce new interpretations of the classic Arthurian stories, with unique art styles and narrative techniques to bring the story to life.
A good way is to establish a common ground. For instance, if both universes have a form of magic, find a way to make those magics interact. Maybe Arturia's magic can be seen as an ancient form that has been forgotten in the Harry Potter world. Another way is through character relationships. Harry could look up to Arturia as a mentor figure, learning from her noble and chivalrous ways.
One interesting concept could be a crossover where Arturia Pendragon ends up at Hogwarts. Maybe she uses her swordsmanship skills to teach the students a new form of magical combat. Another idea is that she could be on a quest related to the Deathly Hallows, bringing her own Arthurian magic into the wizarding world of Harry Potter.
You might try looking on popular digital game platforms like Steam. They often have a wide variety of visual novels available for purchase and download.
Saber from Fate/Stay Night would be an obvious choice. Since she is also related to the Arthurian legend, there could be a lot of interesting interactions between them. They could compare their experiences as king, or even fight side by side against a common enemy.
The theme of redemption also pops up. If Arthur is placed in a darker or more morally ambiguous world, his quest for justice and honor can be seen as a form of redemption for the new world he's in, or it can be a test of his own values as he faces new challenges.