I'm not sure specifically as there could be many novels with this title or related to this phrase. It might be about a story where the protagonist is transported to another world ('isekai' means another world in Japanese), perhaps with adventures, magic, and new characters.
Writing fanfic that involves sexual content is generally not appropriate as it can violate ethical and moral boundaries, and may also go against the terms of use of certain platforms. Moreover, it objectifies the characters in an improper way.
The 'isekai kara kita yuusha novel' likely tells a story full of fantasy elements. The hero coming from another world is a common trope in isekai stories. He could be summoned there by some magic or accident. Once in this new world, he may have to adapt to different cultures, magic systems, and races. His experiences would form the core of the story, which might include battles against powerful foes, exploring unknown lands, and uncovering the secrets of this new world.
One common theme is friendship development. Since kita and bocchi are often characters in a story, their friendship might be explored in depth, showing how they get to know each other better over time.
I'm not aware of a specific work titled exactly 'isekai ni kita novel' being extremely popular. But there are many popular isekai novels in general, like 'Sword Art Online' which has some elements of being transported to a different world.
Since I don't have detailed information on 'orenchi ni kita onna light novel', it might be about a female character's journey in a fictional world. Maybe it involves her facing challenges, meeting new people, and experiencing different emotions. It could also have elements of mystery, love, or self - discovery depending on the genre of the light novel.
Since I don't know the exact novel, I can't say for sure. But usually, there would be the hero who comes from another world. There might also be characters who help or oppose the hero in the new world.
Well, another way to find kita x bocchi fanfic is to check out relevant fan communities. For example, on Reddit, there might be dedicated sub -reddits where fans share their favorite fanfics about this pairing. They may also discuss the plot, characters, and what makes these fanfics so appealing. So it's a good place to start your search.
I'm not sure specifically what this 'isekai ni kita mitai light novel' is about. It could be an isekai story where the protagonist feels like they have come to another world. Usually, isekai light novels involve a character being transported to a different world, often with unique magic systems, strange creatures, and new social structures.
One interesting aspect could be the unique world - building. In many 'isekai' novels, the created worlds are full of magic and strange creatures. This novel might also have a captivating protagonist's journey, like how they adapt to the new world.