User blog comment:B214/Talk About What You Want! 2/@comment-74.77.52.225-20140801025045/@comment-24421137-20140802033212

Plot convenience, I mean in all honesties if Rias was an ultimate class devil, then got to have peerage, she would be really old, and well not appealing to some people, after all this is an ecchi series, where girls looks hold precedence. Any who having a peerage helps devils grow into adults, that is why they get their own peerage at a young age, also the system was originally made for devils, so honestly they were just thinking of themselves when making up the rules, not when a human goes ultimate, after all they are selfish beings :D.