One interesting concept is how characters' fates might change if they had prior knowledge from time travel. For example, Shirou might be able to prevent some of the tragedies that occur in the original story. Another concept could be the interaction between different time periods' versions of the same character, like how a past Archer could meet a present - day Shirou and how their ideologies would clash or align.
In this fanfiction, an interesting aspect could be the new ways of summoning Servants. Instead of the traditional methods, the gamer aspect might introduce a system where Servants are summoned based on in - game achievements or levels. This could bring in Servants that are not typically seen in the original story, creating fresh and unexpected interactions.
Another aspect is the exploration of different endings. Fanfiction can take the Fate Stay Night system and create new storylines that lead to unique conclusions. Maybe a scenario where the Holy Grail War has a completely different outcome, like all the Servants teaming up against a new, unexpected threat.
One interesting concept could be the crossover of character abilities. For example, how a Fate Stay Night character might adapt to the world of RWBY and use their magic in a combat system dominated by Dust and Semblances. Another concept might be the exploration of different character relationships. Characters from both universes could form unique friendships or rivalries that are not present in their original stories.
One interesting concept could be unique interpretations of the Holy Grail War. For example, an OC might have a special ability that changes the dynamics of the war completely. Another could be new relationships between OCs and the existing characters from the Fate Stay Night universe. Maybe an OC forms an unexpected alliance with a Servant, which leads to a whole new storyline.
In such fanfiction, a common concept is the OC's role in the Holy Grail War. An OC with godlike abilities might change the very nature of the war. For example, if the OC has the power to nullify all magic for a short period, it would turn the tide of battles completely. Additionally, the moral and ethical dilemmas faced by the OC can be explored. Since they have such great power, they might struggle with using it for good or being tempted by darker motives. Moreover, the design of the OC, both in terms of appearance and personality, is an important aspect. A well - designed OC with a distinct personality can add a whole new dimension to the Fate Stay Night story.
One interesting concept could be how the original Fate Stay Night mechanics interact with the gamer OC. For example, the OC might have unique abilities that change the way the Holy Grail War is fought. Maybe they can level up in a way similar to a game, which gives them an edge over traditional Servants and Masters.
Some interesting concepts in highschool dxd fanfiction include new forms of peerage systems. For instance, a fanfic could introduce a modified version where there are more diverse types of members. In fate stay night fanfiction, the concept of the Grail War taking place in a different setting, like a modern - day metropolis other than Fuyuki, is fascinating. In the context of fanfiction that combines both, a concept could be the use of Highschool DxD's magic system in the Fate universe, or vice versa, which could lead to really unexpected and exciting story developments.
One interesting concept could be the unique gaming mechanics that are incorporated. For example, how the characters' abilities are translated into gaming skills. It might also include new types of magic or powers that are designed with a gamer's perspective in mind.
One interesting concept could be the crossover of the power systems. For example, how would a Quincy from 'Bleach' fare against a Servant's Noble Phantasm in 'Fate Stay Night'. Another concept might be the character interactions. Picture Ichigo from 'Bleach' having a conversation with Shirou from 'Fate Stay Night' about their respective ideals of justice and protecting others. Also, the different magical and spiritual realms in both universes could merge in unique ways in the fanfiction, like the Soul Society and the Throne of Heroes interacting in some unforeseen manner.
One interesting concept could be how the gamer elements interact with the existing Fate Stay Night universe. For example, the protagonist might have a gamer interface that shows stats for the Servants, which could add a new layer of strategy to battles.