I was thinking the same. It's really weird
My best guess is that it is either based on whichever demon family has the strongest bloodline/power or option 2: perhaps the family name is inherited based on bloodline ability inheritance? They’ve already established that a human concept like friendship was unknown here, so who is to say that marriage in the demon realm is like human marriage?
I think it's because most of the families that have parents with the same abilities are members of a certain clan?
There was clans right? So maybe some parents just married someone from thier clan and even if they have the same power, they have a little difference in details
OR the kids just inherit the fathers power just like the last name and with the clan thing, like Alice's mother has ability that related to seduction, yet alice didn't inherit that and we don't know who is his father
Alice hasn't revealed his bloodline ability and I think it's related to seduction (my theory is that he can change gender but that's just me)
i- I REALLY HAVE A CONTROVERSIAL TAKE THAT MANY OF YALL WOULDNT LIKE BUT HERE IT IS:
i think that because they're demons, whether or not they're inbred doesn't matter i mean, they're totally different beings so applying human standards to them is uhhh idk it's just doesn't work
also i think they're all similar is because it'll be easy to distinguish which family is which and uh it's convenient this way, same designs and stuff :'D
But they seem so proud of lust and seduction?
I mean if they didn't breed they wouldn't care for looks or cuteness or sexiness
They follow they're greed and urges heatedly so in fact i think they're into breeding
It's just that the story doesn't really need that information and to keep the anime and manga+16
yeahh :'D i just really think that Osamu-sensei don't wanna create new character designs and that the purpose of this "incest" looking demon families is for an easier identification also, dont u guys think that iruma's parents also look so much alike? just like the parents of other misfit students??? IS IT JUST ME???? WHAT IF IRUMA IS ACTUALLY DEMON? THAT WOULD ACTUALLY EXPLAIN SO MUCH
In a lot of maga parents looks alike so I don't know about that..
i was watching s4 and i randomly thought up a question; are all the families inbred? how are they all of the same family name with the same power thing? (i forgot the name, forgive me) if not, do they inherit the power after marriage? to give an example of this, both pursons mother and father carry that same invisibility family power.. was it inherited (how would that even work? just getting rid of your identity for the entire first part of your life to have you marital partners same power?), or are they just related? pardon my grammar, i finished finals today