User blog comment:Gilgamesh79/Demonic Energy and Magical Energy/@comment-82.178.102.63-20170829160229/@comment-29963364-20170909193654

A Super-Devil is a Devil that has become so powerful/strong that they can't even be classified as "Satan-Class" anymore.

 Sirzechs 


 * Has 10x (at least) more Demonic Power than the Original Lucifer.


 * Mastered his [Power of Destruction] to the point that it eliminates anything and everything without a trace (he is was even stated that "he is the Devil that destroys phenomena.")

 Ajuka 


 * Has Demonic Power that rivals Sirzechs' (presumed, since it's never outright stated).


 * Specialized Demonic Powers like his [Kankara Formula] grant him the ability to create, change & control any phenomena he desires (he was even stated that "he is the Devil that controls phenomena.")

 Rizevim 


 * More Demonic Power (we don't know how much) than the Original Lucifer.


 * That's really the only reason he's considered a Super-Devil. He's very underwhelming compared to Sirzechs & Ajuka.

Candidates

 Vali 


 * Reaches God-Class (greater than Satan-Class) in his [Empireo Juggernaut Overdrive].


 * Reaches Heavenly Dragon-Class in his [DxD - Lucifer].

 Issei 


 * Reaches Satan-Class in his [Cardinal Crimson Promotion].


 * Reaches God-Class in his [DxD - God] (nerfed).


 * Reaches Heavenly Dragon-Class in [DxD - God] (complete).