The years preceding Localization Crimes III: Nocturne saw a large number of spinoff releases for the series. One of them was Persona, which Act reviewed way before this, but a lesser-known one was Devil Summoner, which is basically identical to the main series so I’m not entirely sure why it’s a spinoff.
The first Devil Summoner sounds interesting from the Wikipedia article, but it was never even fan-translated, so I instead started at Shin Megami Tensei: Devil Summoner: Soul Hackers. Ah, you know something’s a franchise when it contracts colon cancer!