A common theme is power. The dragon slayer often has to deal with gaining and controlling their power in the Highschool DxD universe. Another theme is friendship, as they interact with the characters from the original series.
In 'Highschool DxD Dragon Slayer' fanfiction, a prevalent theme is the exploration of new abilities. Since the dragon slayer is a new element in the Highschool DxD world, their abilities and how they develop are often explored. Additionally, loyalty is a theme. The slayer has to decide which side they are on and who they are loyal to, whether it's their comrades or some other power in the story.
One of the main themes is identity. The dragon slayer character in these fanfictions is usually trying to figure out who they are in the context of the Highschool DxD world. Also, there's the theme of conflict, whether it's with other characters or with the forces of evil in the story. These fanfictions often explore how the dragon slayer overcomes these conflicts.
One common theme is power. Since both Dragon Ball and Highschool DxD have characters with different levels of power, fanfictions often explore how these powers interact. Another theme is friendship. Characters from both series form new friendships or rivalries in the crossovers.
Power. Since it involves dragon gods, a common theme is the acquisition and control of great power. Characters often struggle with newfound dragon god - like abilities.
There's a fanfiction where Issei is a dragon slayer and he teams up with some unexpected characters from the Highschool DxD universe. The story is called 'Issei's Dragon Slaying Adventure'. It delves into his relationships with other characters in a new light as he takes on this new role. He has to face not only the usual enemies but also some who are after his newfound powers.
Power - up is a common theme. Since Issei becomes a Dragon God, the fanfictions often explore his new powers and how he uses them to overcome challenges. Another theme is relationships. His relationships with other characters, like Rias and his friends, might change due to his new status.
Power growth is a common theme. Fans often like to explore how the White Dragon Emperor can become even more powerful and overcome new challenges.
The popularity of Highschool DxD Issei Dragon Slayer fanfiction often lies in the power - up aspect. Fans love to see Issei gain new and exciting abilities like dragon slaying powers. It makes him seem more heroic and gives him an edge in the battles within the story.
One idea could be an OC who is a dragon slayer but has a unique power that sets them apart. For example, they can absorb the powers of the dragons they slay instead of just killing them. This could lead to all kinds of new storylines as they become more powerful and are hunted by both good and bad forces in the Highschool DxD universe.
Start with their backstory. Decide where they came from, how they became a dragon slayer. Were they trained by a master? Or did they have a personal vendetta against dragons? This will shape their personality.
Power - up is a common theme. Writers often explore how the white dragon gains new abilities and becomes stronger in the Highschool DxD setting.
One great 'Highschool DxD Dragon Slayer' fanfiction is 'The Dragon Slayer's Ascent'. It has an interesting plot where the main character uses unique dragon slaying techniques in the Highschool DxD universe. The story also has great character development, especially for the main character as he battles various challenges.