A really engaging Issei Merlin fanfiction is 'Merlin's Guidance for Issei'. Here, Merlin takes on the role of Issei's mentor. The story delves into how Merlin helps Issei grow in strength and wisdom. It has detailed descriptions of their training sessions and the bond that forms between them.
There's a fanfiction called 'Issei's Encounter with Merlin'. In this one, Issei meets Merlin in a magical forest. The author does a great job of portraying Merlin's mysterious nature and Issei's reaction to it. It also has some unique magical elements that make it stand out.
In this type of fanfiction, the relationship between Issei and the legacy of Merlin could be complex. Issei may struggle with the expectations that come with being a descendant of such a powerful figure. He might have to deal with the jealousy or admiration of others in the magical community. Additionally, he could be on a quest to fulfill a prophecy related to Merlin, which would add an element of destiny to his story and drive the narrative forward.
I really like the fanfiction 'Iron Man's Apprentice: Issei'. In this one, Issei is sort of taken under Iron Man's wing. It shows how Issei adapts to the new technology and also how his character develops with the influence of Tony Stark. There are some amazing fight scenes where Issei uses his new - found skills and tech to fight against the villains from both universes.
There's a fanfiction titled 'Female Ddraig's Encounter with Issei'. In this, the author delves deep into how a female Ddraig would view Issei. It's full of character development and new scenarios that are quite different from the canon. For example, their conversations are more nuanced as the gender change of Ddraig affects her perspective on Issei.
One interesting Issei Crossover Fate fanfiction could be 'Issei in the Fate World'. In this story, Issei is transported to the Fate universe and has to adapt to its rules and magic system. He might form new alliances and face off against powerful Servants. Another good one could be where he teams up with Shirou to fight a common enemy that threatens both their worlds.
There is a fanfic called 'Issei's Human Ascent'. In this story, Issei decides to fully embrace his humanity and rejects the more violent and power - hungry aspects of the supernatural world. It has some really interesting character development as he struggles to maintain his newfound human - only identity. There are also some great fight scenes where he uses his wits instead of brute strength.
One great Merlin reincarnation fanfiction is 'The Return of Merlin'. It has an interesting plot where Merlin is reincarnated in a modern world but still has his magic. The story does a great job of exploring how he adapts to this new environment while trying to keep his powers a secret.
One great Merlin Christmas fanfiction is 'A Magical Christmas at Camelot'. It shows Merlin using his magic to bring a touch of real Christmas spirit to the usually dour Camelot. The knights are charmed by the idea of Christmas trees and gifts.
One great Highschool DxD Gamer Issei fanfiction is 'Issei's New Game'. It takes Issei's character and adds an interesting gaming twist to his adventures in the Highschool DxD universe. The story is full of action and the character development is really well - done.
One interesting Issei crossover fanfiction could be where he crosses over into the world of 'Fate/stay night'. In this scenario, Issei's devil powers might interact in unique ways with the Servants and magic in the 'Fate' universe. Another could be a crossover with 'Naruto', where Issei has to face the shinobi world with his devil abilities. There are also some crossovers where he goes to the world of 'One Piece' and has to deal with pirates and Devil Fruits while still having his own devilish powers.
One interesting fanfiction could be 'The Silent Ascent of Issei'. In this story, Issei's muteness adds a whole new layer to his character development. Instead of his usual brash self, he has to communicate in more creative ways, which makes his relationships with the other characters, like Rias, more nuanced and deep. It's a great read for those who want to see a different side of Issei.