Since I'm not familiar with 'tensei kyuuketsukisan wa ohirune light novel', it's difficult to give a detailed account. However, generally, a light novel often has elements such as unique characters, a fictional world, and a plot that may involve adventure, romance or mystery. Maybe this one has a vampire - like character who has some interesting experiences during the afternoon time as the title seems to suggest.
First, check out some well - known Japanese bookstores, both physical and online. They often have a wide range of light novels. Additionally, there are some international platforms that focus on Asian literature. You could also search in forums dedicated to light novels. Other fans might be able to point you to where they got their copy, whether it was from a local store in Japan or an imported source.
I'm not sure exactly as I haven't read it. But generally, a light novel often involves a unique story, perhaps in this one it could be about a vampire (kyuuketsuki) and their daily life including an afternoon nap (ohirune).
Some local libraries that have a good collection of international or Japanese literature might also have it. You can also search in some anime or manga - related forums. Sometimes fans share information about where to find rare or not - so - popular light novels like this one.
I'm not sure specifically as there could be many different stories with this title. It might be about a prince in a reincarnation or isekai setting which is a common theme in light novels.
Power and its implications are also important. He gains certain powers and has to learn how to use them responsibly and also deal with the consequences of having power in a world full of different factions and interests. In this light novel, there are often situations where power can be both a tool for good and a source of trouble.
I'm not sure exactly as I haven't read it in detail. But generally, light novels often revolve around unique characters and their relationships. Maybe it's about a reincarnated sage and his life with a girl.
Some local libraries might also have it. Check with your library's catalogue, either in person or online. If they don't have a physical copy, they might be able to get an e - copy through inter - library loan.