Interesting bits of an interview with the series author. So, instead of Russian, it was meant to be that the female main character was isekai’ed. From the article:
In this version, the reincarnated heroine would speak Japanese to the protagonist, feeling confident that he couldn’t understand her.
The twist would be that the protagonist was also a reincarnated person who could understand Japanese perfectly. This humorous misunderstanding was meant to form the core of a short story.
That would’ve been cool. I’m glad it wasn’t because alya how it is, is amazing. But I’d definitely love to see someone do just that
Some people think a whole genre is just the paper you write any story on.
This pretty much sums up how I feel about world building when I work on my D&D campaigns…
However, the isekai genre’s need for extensive world-building and background explanation led SUN to simplify the story, setting it in the real world instead.
When improvising in a session, it was often just way easier to say something is the fantasy version of [real thing] rather than come up with something whole cloth.