The series does it itself referencing the 72 demons of Solomon as depicted in the Ars Goetia
Well, half of that is Christian stuff.
Demons aren't like that in Judaism. They're just free-agent angels that have to eat and have chicken feet, and generally just inconvenience you (Give you aches and pains, make your clothes wear out for no reason, make you feel mildly claustrophobic...)
It's more stuff like all the kiddush cups (though they're gold in the manga and glass in the anime while most irl ones are silver), his bar mitzvah, the letters/numbers (though they're not used the same way), the ... unfortunate in theme in many ways Many-ears arc (their story is our story, but the land they annex was actually vacant... Free Palestine), all the characters with prominent peyos/peyot (pronounced "pay us/pay oat")... There's more, but I'm firmly convinced that if I go to Shabbos services the next time I'm in Japan, Nishi will be there.
The way and which elements ramp up over time indicate to me that Nishi is converting or converted, and converts go to services more often, generally.
I don't know that I'll actually end up talking with them, or know if I am, but it's a funny thought.
Strong indications sprinkled in that it's Conservative/Masorti Judaism, which is ironically one of the more progressive strains of Judaism. Basically, tere are a lot of things that focus on traditions and it's really heckin queer.
Aaaanyway, it's heckin awesome in every way. This series has everything.
Action, laughs, drama, romance! Queers, polycules, Judaism!
Femboys and lesbians!
