User blog comment:Mnzombie/Issei's Peerage/@comment-3965848-20140328082025/@comment-3965848-20140328090752

I also said that he'll become a High-Class Devil after that long meaning he won't have a complete set till then. And when who knows when will he become one, Devils live for a long time so it be longer the, exact number doesn't matter I'm just saying it will be a very long time.