User blog comment:Jopjopjop/Volume 18 Spoilers/@comment-14716567-20140620203319/@comment-202.152.195.67-20140620221017

And do you think Vali will be stuck using EJOD only for a sec ?? NO, It's just a matter of time until Vali could maintain his EJOD for a longer periode. I think it's quite suitable for Issei to gain some power up, he could not even fight Cao Cao properly and i also think Cao Cao's skill is also improving now. Once Cao Cao is able to master his True Longinus then Issei and Vali would be in dangerous situation ( Thank God he is on their side at least for now). Well, even with the power of Rias's boobs could not make Issei "win" against Cao Cao last time.