User blog comment:B214/Volume 22 spoilers/@comment-24552694-20160923205503/@comment-30048084-20160925190839

I think from what I have read you inherit the same rank as your parents even if they were reincarnated devils so all of Ise's children could be high rank devils but have no interest in having their own peerage at the time of Ex. If it is a case by case situation considering Ise's position in underworld society they will all be high class devils.

If you think about it maybe Ise and Akeno's son Kurenia is a high class devil but is more concerned with his own "hobby" researching sacred gear and thinks having to manage a peerage would take too much time.

another possibility is that the parents have a certain amount of say in the matter of them obtaining evil pieces or a devil must fulfil certain other requirements to qualify for evil pieces such as a certain level of combat capabilities, intelligence( the underworld's schools test marks)

In Ravel's case I think she would retain her rank even if she marries Ise because he is himself a high level devil(eventually ultimate devil) regardless of the fact that he is reincarnated.

I agree with sky-Dragon-Twilight most likely becoming a evil piece if you are a high class devil nullifies your rights to create your own peerage