Responses
they probably called them “half breeds” because they were not born from the empress or another wife their father took in. Rurahel doesn’t seem to have a noble status in society either so they are most likely referring to class. i doubt people outside the royal family know
They usually call them low borns, commoners, or bastards so I think it was about them being different half human and half spirit
So this is what they meant by the the twins only being half breeds too. I was confused about this for a while because the queen or anybody he sleeps with are all human and probably from different royal families (unless incest is going on) which means that all the children would be half breeds or none of them would. But Rurahel is literally not even human, meaning that they are only half. This all makes sense now