Well, without having read 'Floor ni Maou ga Imasu' Light Novel, it's hard to say exactly. However, light novels typically blend elements of fantasy, action, and sometimes comedy or drama. Given the title, it could center around a demon king's presence on a particular floor. It might involve characters trying to deal with the demon king, whether it's through combat, negotiation, or some other means.
I'm not very familiar with this light novel specifically. But generally, a light novel often features unique characters and a fictional story world. It might be about some kind of adventure or relationship in a setting where there's a'maou' (demon king) involved. Maybe it's about the interactions that take place on a certain 'floor' within this fictional universe.
Since I haven't read the 'Floor ni Maou ga Imasu' Light Novel, my understanding is limited. But light novels usually have a well - crafted plot. In this case, the 'floor' in the title might be a significant location within the story. The'maou' being there could be the main source of conflict or mystery. There could be heroes or other characters who are on a quest related to this demon king on the floor. It could also explore the backstory of how the maou ended up on that floor and what consequences it has for the world or the characters in the story.