Do the factions have specific demographics to keep in mind? I know groups that have similar things would say like "this group is primarily African-American" or something so I'm just wondering if that applies here!
Hi and thank you for your interest in kadeu!
While demographics along the lines of race are not used, though most of the city's citizens have Asian last names but that's about it, there are certain other identifiers.
Along the lines of species we see Spellswords only found in Spades, Fae predominantly residing in Hearts (then Diamonds), Elementalists are more common in Diamonds, and the majority of Shifters are within Clubs. These identifiers are historic but given defection and interfaction mingling, the species have blended some, save Spellswords and Fae.
Employment is also another identifier. A being that introduces themselves as an artist will almost always have another assuming they are Diamond as would anyone that offers protection for hire would have another assuming they are Club. Any military rank announces the Spades, and any adult entertainer announces Hearts.
Again these identifiers are historic but should not bar your creativity. So long as a character holds to lore fundamentally, stepping outside these identifiers could only bring more life to our world.