User blog comment:B214/Question and Answers 4/@comment-24098614-20150214225932/@comment-24502975-20150215174959

Since Diehauser Belial is Maou-class, obviously Shalba and co. with Ophis' snake aren't. Shalba just assumed he was (but, just like he assumed Juggernaut Drive was weaker than it actually was (and it was incomplete), he was wrong).

Now, assuming [Worthless] can nullify Sirzechs' POD, Belial should be able to defeat Sirzechs. Those who wield the Power of Destruction have never shown the ability to use regular offensive demonic power. With that in mind, the only Maou who could defeat him would be Ajuka (whose Super-Devil status comes not from a House trait, but from the ability to control all phenomenon).