User blog comment:B214/High School DxD DX.4 discussion/@comment-2601:8C:601:5692:3D30:770C:CE5:1085-20170725134222/@comment-120.188.92.13-20170729162752

^ Well, 72 pillars are considered as nobilities and those who carry their names are considered as nobles or referred to high class devils. It's more about blood relation than anything and i believe you are quite aware that Devil values Bloodline so highly. Taking test and such is just for Low class devils to advance their rank so it's not for those who are born as High-class Devils. Once the young High class devils have come of age then they will be given a choice either to take EP and become a king ( like Rias, Sona, Sairaorg etc) or serve as a peerage of somebody else ( like Ravel, Sektos Barbatos, Veves Furfur etc)