User blog comment:B214/Question and Answers 6/@comment-5.36.182.185-20161001040526/@comment-9595671-20161001145752

I have a feeling they are, Creuserey spoke like the original ones did as mentioned on the Four Great Satans' page. In a way, I feel the Four Great Satans were the previous generation of the Rookies Four back in their time, but at an even higher degree.

The descendants relied on their inherited demonic power, but Sirzechs and the others all trained and even mastered their powers and abilities (I think Ajuka outright created his own due to how his Kanakra Formula was described) which made them even stronger.

It's also why Grayfia is a Satan Ranger, the fact she and Serafall once fought for the Leviathan position likely means Grayfia is as strong them. Had the 7 Satan system existed when the series began, I'm positive Grafyia would have taken one of the other three spots.

Plus if the Bibilcal God and the old Satans weren't on the Top 10 like Sirzechs and Ajuka are... well it's not complete dispelling all doubts proof, but if two Satans are that strong, then I think Serafall and Falbium likely surpaassed their predecessors too.