The Persona games are certainly the most popular spinoff that branched off from the Shin Megami Tensei series, but it might surprise some fans to know that Persona has more in common with Megami Tensei, the series that preceded Shin Megami Tensei. Where most Shin Megami Tensei games involve surreal, apocalyptic settings, the Persona franchise focuses on high schoolers who become immersed in a secret, supernatural world. Both series incorporate a variety of creatures pulled from real-word myths and religions, but the juxtaposition of a demon summoning RPG that is also a coming-of-age story closely aligns Persona games with the original Megami Tensei, and the novel it was based on.
https://screenrant.com/persona-smt-inspiration-shin-megami-tensei-horror-novel/