User blog comment:SpookyBoogie27/Light Novel Spoilers/@comment-174.116.187.102-20130326222653/@comment-33447191-20130326223142

Mephisto Pheles isn't a Super Devil since he is from the same generation as "the old Maou". He is so old that he has met Rias' Grandpa, Great Grandpa, and Great-Great Grandpa....