User blog comment:B214/Volume 23 discussion blog/@comment-73.46.6.122-20170318162505/@comment-10330822-20170319035329

No, he specificially stated he's as strong as Grayfia, who is confirmed Satan-Class, so yeah, he's Satan-Class.

No, that doesn't mean he is as strong as Diehauser, but he would be in the same league.

Personally, what we know, is that Sirzechs, Ajuka, and Rizevim were the top devils, the Super Devils, which is like ultimate Satan-Class.

Diehauser may very well be stronger than Serafall and Falbium, but he can't be promoted if there is no opening. As for Grayfia and Euclid, Grayfia competed with Serafall for the Leviathan position, but lost it to her, implying that Grayfia is weaker than Serafall.

Personally, this is what I suspect the power order to be.

1. Sirzechs

2. Ajuka

3. Rizevim

4. Diehauser

5. Falbium

6. Serafall

7. Grayfia/Euclid