From what I understand, it's better not to look at this story through OMEGAVERSE lense. Just understand that niers are normal humans but if they mate with a BOB then they can get pregnant irrespective of their gender( its not coz they're like omegas but more like BOBs have the power to get anyone pregnant). BOBs can get each other pregnant no matter the gender. They are highly sexual beings. Very instinctual. Gender doesn't matter to them. And all of them have heats. There's no alpha or omega here. It's a different concept.
Hope this helps. Any other clarification you might need i'll happily answer. (๑•ㅂ•)و✧
From my understanding male niers can only get pregnant if they pay for an expensive biological alteration. I think they mention that that is why it’s mostly elite (aka rich?) people who’ve payed for it.
So Niers are considered the most lowest in this world and can get pregnant but dont have heat? Like omega? but sirens can also be pregnant? Are Vamps like Alphas but instead they cant love Niers?
Yall better help me, damn the art is pretty but the system of this story is hard.