User blog comment:Crimson and Darkness/Volume 24 discussion blog/@comment-30329599-20171121175750/@comment-2607:FB90:A0BC:18A4:0:49:6F66:B601-20171122101334

Basically in that form Rias can stop and ridirect powerful attack and also has some of Gaspee's darkness abilities in addition Rias power of destruction is increased greatly. The problem is Rias can't maintain the form for long and it takes it toll on her body. But Rias was able to fight on par with Fenrir at 80% of his full power before she was force to give up. So Rias in that form is God Class. Definitly stronger than Issei's Cardinal Crimson True Queen.