User blog comment:B214/Question and Answers 6/@comment-82.199.202.234-20160523154710/@comment-24.113.252.213-20160523235419

Entire clans have been stripped of their High-Class status just for having "mixed" blood in them. Meaning that they breeded/bred with anything other that a pure devil.

Although, I wonder if they are okay with a High/Ultimate-Class devil marrying and having kids with a Commoner Devil (as in the pure devils who aren't nobles).