One aspect to consider in Charles Xavier x OC fanfiction is the unique dynamic it can create. An OC (Original Character) can bring a fresh perspective to the X - Men universe. For example, the OC might have a special power or a different background that challenges Charles Xavier's beliefs or ways of doing things. This can lead to interesting character development for both the OC and Charles Xavier.
A common trope is the 'fish out of water' situation for the OC. They might be a new mutant arriving at Xavier's School for Gifted Youngsters and feeling out of place, which then draws Charles Xavier's attention. This trope allows for a lot of character exploration as the OC adapts to this new world with Charles as their guide.
Charles Xavier's fate in the comics is not straightforward. Sometimes he's alive, sometimes he's dead. It all depends on the writer's creative decisions and the direction of the story at that time.
Well, in the current state of the comics I've followed, Charles Xavier remains deceased. However, comics have a way of bringing characters back or introducing alternate timelines and universes, so there's always a possibility for his return in some form.
A common theme is his vision for a future where mutants and humans coexist peacefully. In 'Xavier's Dream of Harmony', this is the central focus. His connection to the minds of others is also explored. For instance, in 'The Mind of Xavier', it shows how he uses his telepathic abilities in different ways. And his past traumas and how they shape his present actions are themes in fanfics like 'Charles Xavier: Shaped by the Past'.
Another theme is his relationships. This can be his friendship with other mutants like Magneto or his romantic relationships in some fanfictions. 'Xavier's Love Interest' is a fanfiction that focuses on a possible romantic relationship for Xavier, which adds a different dimension to his character.