The first volume of 'Re:Zero − Starting Life in Another World' is quite popular as it sets the foundation for the whole story. It introduces the main character Subaru and the strange world he finds himself in.
Sure. 'Re:Zero − Starting Life in Another World' is a great one in the list. It has an interesting story about Subaru Natsuki who is suddenly transported to a fantasy world and has to face various challenges and mysteries.
Re:Zero is indeed a light novel. The story is rich and detailed, which has made it very successful. It has also been adapted into anime and other forms of media.
It's hard to give an exact number because the publication of Re:Zero light novels is an ongoing process. You can check the official sources or dedicated fan sites for the most up-to-date count.
A Konosuba - Re:Zero light novel crossover might explore the different magic systems. In Konosuba, magic is often misused or has unexpected results, while in Re:Zero, magic has a more serious and often dangerous undertone. The crossover could play with how the characters from each series view and interact with the other's magic. Also, the settings are quite different. Konosuba has a more light - hearted and comical fantasy world, while Re:Zero's world is darker and full of political intrigue. Combining these two settings could create a really unique story.