User blog comment:B214/Shin DxD 1 discussion/@comment-36663391-20180920083134/@comment-34061653-20180921153414

It terms of raw power Crom is above Ddraig and Albion but that's about it. Ddraig and Albion's abilities closes that gap. Vali was able to fight with Crom because of his abilities. It's true that Vali is faster than Crom but that speed became irrelevant due to Crom reading him with intuition. In my opinion Ddraig and Albion could beat Crom if they use their signature finishers but this isn't a deathmatch.

In Issei's case, he has more raw power than Vali but below Crom but he can match up the gap it with his 2 dragon slayers and abilities.