In Diluc x Reader fanfics, the character of Diluc is usually depicted as he is in the original game, with his brooding and mysterious nature. The story could start with a chance encounter between the reader and Diluc, and then gradually develop into a more intimate relationship. Writers might focus on how Diluc's past affects his relationship with the reader, adding depth to the story.
Well, 'Jean x Diluc hentai manga' usually refers to manga that depicts sexual or explicit content involving these characters. This kind of material is often considered outside the mainstream and may not be appropriate for all ages.
Another theme could be adventure. Since Diluc is often involved in various adventures in the game world, the fanfic might have the reader joining him in those escapades, strengthening their bond through shared experiences.
Another theme could be adventure - based. Since they are both important characters in the Genshin Impact world, they often embark on adventures together in fanfics, which also helps to develop their relationship further. For example, they might go on a quest to save Mondstadt from a new threat and during that, their feelings for each other grow.
Fanfiction.net might also be a good place. Although it has a wider range of content, you can still find some interesting 'diluc x jean' fanfics. Browse through the Genshin Impact section and search specifically for their pairing.
It's hard to say for sure. The availability of Venti in the story depends on multiple factors such as the story's genre, setting, and the author's intentions. It could be possible, but you'd have to look closely at the story's details to know for sure.