So having just learned about this there's some very curious things about this. It seems like it might include the Amala expansion book that Tokyo Conception got, since the page count is almost 200 pages higher than the original book and that's a
lot more even with the difference in space when writing japanese vs. english.
It's also standing out to me that this is Tokyo Conception, the game's fourth edition, and not Mato Tokyo 200X, which was the game's 5th edition and to my knowledge the most recent one; it also got a whole bunch more supplements. Picking up a game that's been running since 1993 and not starting at it's oldest
or newest edition is an interesting choice, particularly since as far as I know the last book for the game was published over a decade ago.
I know Lionwing has done other localisation, I just hope this one is good. I have the same fear I do with the FFXIV ttrpg - that there won't be any PDFs because it's a licensed property, which'll mean it'll be near impossible for me to play with my group :\
I guess it depends on your definition of what an isekai is, but Nocturne's story is not really 'normal person finds themselves in an alternate fantasy world.' It's a post-apocalyptic story where you are turned into a demon by mysterious forces. The planet your on is Earth still
Isekais don't
have to be alternate worlds, or even fantasy. Some of the most famous isekai could also double as time travel anime (such as InuYasha). The protagonist typically just has to be displaced from the world they know to a time or place mysterious and alien to them. I'd definitely consider SMT3 an isekai, even if it's not the first thing that would come to mind.