User blog comment:SpookyBoogie27/Light Novel Spoilers/@comment-4823600-20130209134048/@comment-1359322-20130209145314

1. The author already mentioned that the Great Red Issei combination is a one time only

2. Like what the contributor wrote Rias simply didn't realize it was Sirzechs and the others maybe she was too focus on the ceremony.

3. Actually that doesn't mean much take Jeanne for an example her Blade Blacksmith is a Dragon made from Holy Swords.