User blog comment:B214/Question and Answers 2/@comment-24098614-20140609194726/@comment-1359322-20140609233631

They can't. How many times do i need to explain, even if a Reincarnated Devil reaches High-Class or higher, they are still the servants to their Master. Even if Issei reaches High-Class, he will still be Rias' Pawn. They can't face each other in Rating Games.