User blog comment:B214/Volume 22 spoilers/@comment-154.242.38.77-20160819230516/@comment-197.113.24.52-20160822005236

I meant that Vali can unleash the full power of Albion now that he has received the "blessing" from Ophis, but Issei's new form is ultimately a mix between Ophis's power and Issei's original power, The true Queen and so Ddraig, And that means that Issei still doesn't reached the Heavenly Dragon-class since he doesn't have full control in Ddraig's power, of course using Ophis's infinite power and by that I mean [Diabolos Dragon] weither it's the original Dragon Deification or the Pseudo one he can beat Vali, but only using Ddraig against Vali, Issei wouldn't be able to exceed him. Issei already stated that he doesn't like using Ophis's power since she was an existence that only wanted "peace". So on their final dual, Issei would be obliged to use only Ddraig's power against Vali, as for him he'll only use Albion and on his Lucifer heritage i must say, so it will be a [True Queen] against the [Diabolos Dragon L]...It seems hard to imagine Issei winning over Vali on that situation