The Four Great Empire are the powers which rule over the continent in which Dana is reincarnated at.
Each of the four great Empires strongest experts are their respective Emperors, each being a ninth rank Houtian however some of the Empires are naturally stronger than the others.
The Holy Empire is the strongest of the four, mainly because of the influence of the church as there are many patriotic believers in the church across all four great empires, so therefore they have the largest influence and number of experts. However, even though they are the strongest, with having Six Houtian experts including the Pope of the Holy Empire which is a 9th Ranked Houtian they are still wary of the other Empires as if they engaged in a full on war then, the other Empires when threatened will likely create an alliance to oppose their Empire causing them major causalities!
The Azure Empire is the second strongest due to Devils Peak, as it is the largest inhabitant of Spirit beasts among the four continents, as they tax cultivators which come primarily just to hunt spirit beasts in the forest they have gathered a huge amount of wealth, thus creating a large amount of experts. Although not comparable to the Holy Empire, they are still a strength to be rivaled with! Previously they had Lord Evergreen, who even had comparable battle power to each of the strongest experts of each continent, however he later died in an ambush by the Eranyth Empire and fell against the three strongest experts of Eranyth Empire as a result of their combined attacks, and being injured due to a sneak attack. As mentioned they previously had four Houtian cultivators including Azure Emperor, but now one has been killed by Dana making it three.
Eranyth Empire is the third strongest between the four great empires, they are slightly weaker then the Azure Empire, the only reason they can be slightly weaker even with the Azure Empire obtaining the advantage of owning Devils Peak, is that they have a large amount of the best alchemists in the Azure Continent. With use of this alchemists they create many of the top pills which the four continents buy in mass, providing them with a large amount of wealth. As a result of this wealth the Eranyth Empire has raised a large amount of strong cultivators, and has three Houtian Ranked Cultivators now the same amount as the Azure Empire!
The last and weakest Empire is the Orthos Empire, although the weakest they are by no mean an Empire which can easily be trampled on. They have two Houtian Ranked Cultivators. Reason why other Empires are afraid to invade Orthos Empire is if the Orthos Emperor disregards his life he can deal a severe amount of damage towards the opposing Empire, thus weakening their forces by a large amount therefore this will cause another Empire to take advantage and wipe them out something which no Empire believes is enough of a risk to invade Orthos Empire.
This is the backgrounds of each Empire, which basically details going from the strongest to weakest, each Empire has a large amount of Qi Circulation cultivators, however the main strength of each force is their Houtian experts. It is another one of the reasons the Azure Emperor is so maddened as he not only lost the future heir and most talented son, he also lost an extremely valuable Houtian expert! Houtian experts are scarce and exceedingly difficult to cultivate, showing just how strong the Holy Empire is to actually have six.