No, Rh negative is not an unhuman blood type. It is simply a blood type that is missing the Rh D antigen. Nothing else is different about the blood, it is simply missing one of about 50 antigens and is one of around 32 types of human blood group classifications based on different groups of antigens… Human blood has all sorts of combinations of antigens, the presence or absence of some of them are more dramatic in impact than others when it comes to blood transfusions or mothers with infants in the womb. Its why people with “type A” blood cannot get a blood transfusion from someone with “type B” blood. Rh negative is just one more type to take into consideration.
So, no, neither you nor anyone else with Rh negative blood are the offspring or descendant of fallen angels.