I'm not sure specifically which 'corazon traicionado' story you mean. It could be a song, a book, or a local tale. Without more context, it's difficult to provide the full story.
Issei develops by facing various challenges. Each encounter in the harem and with the milf - hunting situations makes him grow. He becomes more confident over time.
Issei's strength in the light novel is significant. His power increases through training, experiences, and unique opportunities, making him a formidable character.
Well, it makes him seem more like a regular, well - rounded person. In the original, his perverted nature is quite prominent. But in these fanfictions, he becomes someone you can look up to. He might be seen as a role model for younger readers who don't want to be associated with the perverted side of his character.
Maybe he just doesn't like the way supernatural elements are often exaggerated or misrepresented in fanfiction. He might prefer more realistic or traditional forms of storytelling.
A great 'rias and issei fanfic' often has a strong focus on their relationship. It should show their growth as a couple, like how they overcome misunderstandings and support each other. For example, in some fics, Issei's determination helps Rias in her devil duties, and Rias's wisdom guides Issei in his power development.
In Highschool DxD fanfiction, a common trope regarding Issei is his growth as a character. He often starts as a pervy and weak character but gradually becomes stronger and more noble. Another aspect is his relationships, like his complex interactions with the various female characters in the series.