1-Stellar Class (Planets)
2-Stellar Sub-Class (Moons)
3-Supreme Class (Continents)
4-Definitive Class (Islands)
5-Maximum Class (Mountains)
6-High Class (City)
7-Middle Class (City Block)
8-Low Class (Superhumans to Building)
(A/N: This is only a reference to what each rank in power is capable of doing, but there are always exceptions like Issei or those who own a Longinus. I created this ranking system because there will be some characters from To Love Ru who obviously do not belong to DxD and cannot be classified using the same criteria. So I invented this 'level of power' to avoid confusion. If you're wondering why the villains who surpass the Final Class don't go around causing chaos, it's because everyone is divided into territories, such as the pantheons where the gods reside. Do you think those gods would allow them to cause chaos or something like that?)
(A/N: This may change in the future, leave suggestions).