User blog comment:B214/Light Novel Volume 16 spoilers/@comment-1884090-20131122135652/@comment-1359322-20131122171726

First of all welcome to High School DxD Wikia. And yeah Rizevim is a Super Devil and can negate Sacred Gears. As for Issei, he would probably have to look for other methods to fight, personally i think he'll take in more Dragon power since he isn't good with demonic powers. As for Ascalon, kinda like i always said not really the best weapon against the Super Devils cause Devils with high demonic power can withstand the Holy Swords. The Dragon flames can be powered up with boost and Ryuuteimaru might take time to evolve. Well unless if Issei depends on his Oppai Pawa again, he'll probably have to train in many things before he could fight Rizevim.

As for the others, well Akeno would probably try to power up her Raikoryuu while Rias might try to power up her new move or come up with something new. As for Yuuto, it's best that he avoids the Demon Swords, the Demon Swords are cursed so it curses the user with every use, in the sever case it shortens the users life. Maybe it would be better for Yuuto if he trains like creating the Ultimate Holy Demonic Sword that rivals Caliburn and Gram. Asia isn't suited for combat with her personality and all though having Fafnir should be enough. Xenovia can master the Ex-Durandal. Not sure of Irina. Rossweisse is perhaps the one with the most potential to grow among the females.

Vali is already powerful but he hasn't reach Rizevim's level yet, needs more years of training but like Azazel said, he'll be able to kill Rizevim eventually. Saji achieving Balance Breaker is expected already as to when no one knows. As for Sona's teams, we have yet to seen their full potential since they are only shown fighting several times only, but yeah they are undoubtedly the 3rd strongest team for the young Devils. Sairaorg is already hacked but could still be stronger, maybe he could use a finishing move.