User blog comment:B214/Shin DxD 1 discussion/@comment-32252462-20180720191133/@comment-28884330-20180720192018

Issei in his Crimson Armor without partial DxD fought on par with Baraqiel, who is at the level of a Seraph. Therefore Dulio is stronger than a Seraph by taking his Sacred Gear into account, and henceforth the other Seraphs most likely cannot fight at his level.