Issei's death would have a profound impact on the entire school. The girls who had a crush on him would be in mourning. His classmates would be shocked and confused. The teachers might be concerned about how the students in the Occult Research Club are handling it. Some of the devils from other families would see it as an opportunity to gain an advantage over Rias' family, while others might be secretly sad as Issei had made an impression on many in the devil community. Overall, his death would send shockwaves through the various relationships and power dynamics in the Highschool DxD world.
Rias would be devastated. Issei was not only her servant but also someone she had deep feelings for. She would likely go into a rage at first, vowing to find and punish whoever was responsible. Akeno would be heartbroken as well. She and Issei had a special bond, and she would be in mourning for a long time. Kiba might feel a sense of guilt, wondering if he could have done more to protect Issei. Asia would be in shock and constantly pray for Issei's soul, hoping for some kind of miracle.
The members of the Occult Research Club would react in different ways. Xenovia might see Issei's death as a sign of the harsh reality of their world and become even more determined to fight against evil. Gasper would probably be very scared and withdrawn, as Issei was one of the few people who made him feel safe. Rossweisse would be sad but also try to keep a level head, knowing that they need to figure out what happened. They would all have to deal with a big void in their group without Issei around.
Rias would be initially cautious. Since she was so used to Issei, the new OC would be an unknown factor. She would likely test the OC's loyalty and abilities. Akeno might be intrigued by the change, seeing it as an opportunity to get to know someone new. Koneko, on the other hand, would be more reserved and take her time to warm up to the OC.
Issei would probably be the first to want to fight Thanos. He's always eager to prove himself and protect his friends. He might initially underestimate Thanos due to his own growing power and confidence, but soon realize how powerful Thanos really is. Rias would be more cautious. She would likely try to gather information about Thanos first and then formulate a plan to either fight or negotiate with him.
One possible plot could be how the Occult Research Club copes with Issei's death. They might struggle to move forward while also trying to figure out who was behind his death. Maybe they suspect a powerful enemy from the Underworld or a rogue devil. Another idea could be that Issei's death sets off a chain of events that leads to a new power struggle in the supernatural world, as different factions vie for the power he once held or the influence he had over certain areas. And his friends could be visited by his spirit in dreams, guiding them to uncover secrets he didn't have time to reveal before his death.
Issei, being the hot - blooded character he is, would probably be excited to meet someone as powerful as Naruto. He might challenge Naruto to a friendly spar at first, hoping to learn from him and test his own strength. And as he gets to know Naruto better, he could start to see him as a brother - in - arms, especially if they face common enemies together.
It could start with them being forced to work together on a mission. At first, they might clash due to their different personalities. Issei is more impulsive and Yubelluna is more reserved. But as they face difficulties during the mission, they start to understand each other better. For instance, when Issei rushes into a fight without a proper plan, Yubelluna scolds him but also helps him out. This back - and - forth gradually turns into a more affectionate relationship.
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.
Issei would probably be both scared and excited. He's used to dealing with powerful beings, but the Ghost Rider is on a whole different level. He might initially try to fight him out of bravado, but soon realize he's outmatched. Rias would be more cautious. She would see the Ghost Rider as a potential threat to her peerage and would try to figure out his motives before taking any action.
For Issei, in fanfiction, he could be developed by giving him new powers. For example, he could gain some of Ophis' power in a special encounter. This would not only make him stronger but also force him to learn how to control and use it, which could lead to a more mature Issei. His relationships could also be developed further. With Ophis, he could start to understand her better and become more than just an acquaintance.
Some characters might be intrigued. For instance, Issei might be curious about Fem Naruto's fixation on Ophis. He could see her as an interesting addition to their world and might try to understand her motives. Rias, on the other hand, might be more cautious. She would likely be concerned about how Fem Naruto's admiration for Ophis could affect the balance of power in their territory.