I don't know for sure. Maybe you could try looking up detailed summaries or reviews of the light novel to get the answer you're looking for.
No, he doesn't. He gets into some really tough spots, but he always manages to come out alive.
There are fanfictions where Issei leaves to protect others. He might learn of a great danger that is coming and decides that the best way to keep his friends and loved ones safe is to remove himself from the situation. So, he leaves, hoping that the enemy will follow him instead of targeting those he cares about.
When Issei leaves in fanfiction, one possibility is that a new character or group emerges to fill the void he left. This could bring about new alliances and rivalries. His departure might also cause some characters to question their own beliefs and loyalties. For instance, Rias might reevaluate her leadership style and the goals of the club without Issei's unwavering support.
Yes, there might be. There are a vast number of fanfictions out there for various combinations of popular culture elements. Since Highschool DxD has a large fan base and Godzilla is an iconic figure, it's not unlikely that some creative fans have combined the two in a fanfiction. You can try searching on popular fanfiction websites to find such works.
There could be. Fanfiction writers are known for their wild and creative crossovers. Given the popularity of Highschool DxD and the unique concept of Guyver, it's entirely possible that an Issei - Guyver fanfiction exists. You might want to check popular fanfiction websites like Archive of Our Own or FanFiction.net. Just search for relevant keywords like 'Highschool DxD Issei Guyver' and see if any relevant stories pop up.
In some fanfictions, Issei's character develops by becoming more mature. He realizes the consequences of his actions more deeply. For example, when he uses his powers, he starts to consider the collateral damage and tries to minimize it, which is a big step from his more impulsive self in the original story.
Fem Issei can influence the story's themes. In Highschool DxD, themes like masculinity and male - centric power struggles are common. With Fem Issei, themes of femininity, female empowerment, and different forms of leadership can emerge. This can completely transform the tone of the fanfiction, making it more about female agency and how she challenges the existing norms of the devil, angel, and fallen angel societies in the story.
In many fanfictions, Issei's character develops in terms of power. He starts as a relatively weak character and gradually becomes stronger through training and various challenges. For example, he might learn new techniques from a mysterious mentor or gain new powers from a magical artifact.
Yes, there are likely fanfictions out there with such a concept. In the 'Highschool DxD' universe, there are so many creative interpretations by fans. Some fanfiction writers might explore the idea of Issei taking on a Satan - like role for various reasons, perhaps to add a new twist to the story, explore different power dynamics, or to create unique character relationships.
One great Issei and Koneko fanfiction is 'The Bond of Opposites'. It delves into their relationship in a really interesting way. It shows how Issei's brash nature and Koneko's quiet demeanor play off each other.