Power Scaling
It is difficult to make a proper power level in dxd as we all know so for all races that AIN'T GODS the power level will be :
LOW CLASS, street-to-town-level destruction
MID CLASS, Town-to-city-level destruction
HIGH CLASS, City-to-district-level destruction
ULTIMATE CLASS, District-to-state-level destruction
SATAN/LEADER CLASS, State-to-country-level destruction
TRANSCENDENT CLASS [Those who have started to convert their power to or connect their power to a concept or domine, and before you all start no god has complete control over a domine or concept, well at least in dxd], Continental-level destruction at minimum
Now all classes have three sub-divisions: low, mid and peak, but from the ultimate class these divisions are hard to define, hence there will be none.
Gods are all beings born or created, idk, at High class, but not all of them are fighters, they need to train their concepts for them to be fight-ready. Gods are classified as:
REGULAR GOD, high-class beings of other races can fight them, those in lower classes can also fight them depending on the person
LOW-LEVEL GODS, Demeter etc.
MID-LEVEL GODS, Hermes etc.
HIGH-LEVEL GODS, Artemis etc.
GOD-KINGS, Zeus, Indra etc.
PRIMORDIALS, Nyx, Shiva etc.
[Note to all readers, I do not mean to insult or offend any person's religion, thank you all for reading my FF]
Regarding the GODs they can grow to become stronger and can become higher level gods if they train which is rare hence they remain the same for a long time, they ain't like dragons who grow stronger till around Dragon-King level just by living, but since dragons are well them they get killed in fights.
Heavenly Dragons are dragons somewhere in between satan and transcendental class, but closer to transcendental beings, as they have concepts that they use in battle
Now, Super Devils are those who can go head to head with god-kings at minimum, they have the potential to fight primordials, would they win that is a question, like Sirzechs v Shiva, it is mostly Shiva who will win as he has the experience and more control over his power, but Sirzechs v Hades, Sirzechs will mostly win, but will have a hard fight.
Weekly Power Status
-- Power
Ranking 
-- Power
stone