User blog comment:B214/Question & Answers 5/@comment-172.56.4.197-20150612132800/@comment-24098614-20150614051943

Sirzechs is Op because the Super Devils are like a genetic anomaly if you want to explain that because they are very far from the norm, and you are only seeing Sirzech using a fraction of his power because he has a True Form that he keeps sealed away for a good reason.

You already see why the Old Maou Faction members despise them not because of what they did but they are jealous in how powerful they are compared to them because Devils might have ambition and greed as motivating factors but pride always comes first.