So essentially, Glory City and the world we know of right now exists on a continent called the "Tiny World." Cultivation is limited to Legend rank (what people like this Long Sha guy and the city lord Ye Mo are), and you can't go higher than that barring being becoming essentially a god. MC is pretty low on the scale but trashes the guy he's fighting right now, and after this arc onwards he becomes progressively stronger faster than the current rate of the story (I think in like 3-4 arcs he's legend rank too). But, newsflash for people other than the MC, the "Tiny World" isn't all that; there are other places in the world, and what they end up heading to is a place called the Draconic Ruins Realm, where everyone is way stronger than the people from Glory City.
From Legend rank, stages go from having 5 stars each to being broken into 9 stages, and you go from to Heavenly Fate, Heavenly Star, Heavenly Axis (between Heavenly Star and Heavenly Axis are where your martial artists in the Draconic Ruins Realm generally stand, and considering each rank exponentially increases in power these people would TRASH anyone from the Tiny World), Dao of Dragon (where the MC and most of his group like his two waifus and his homeboys currently are in the web novels), Martial Ancestor (where the strongest people are/are projected to be in Draconic; sect leaders, their elders, etc. By this point, you're so fucking strong you literally can't be reborn as your soul merges with your body, you take fucking forever to cultivate higher, like from stage 6 to 7, and you live for hundreds if not thousands of years), Deity rank, Emperor, and then Supreme as the highest known. Deity, Emperor, and Supreme have no stages mentioned thus far, but it's likely that they do.
The Sage Emperor, aka the big bad that you can see at the very beginning chapter where our MC remarks "where am I?! I should be fighting the Sage Emperor and his generals right now!" is at the Emperor rank. Same with Emperor Kong Ming, aka the guy that hid the temporal spirit book pages, had that underground hidden tomb that MC raided early on with his blue haired waifu (along with a bunch of his classmates, all around chapters 40 or so), as well as that one speech on the stone tablet that talked about "at 16, I reached legend rank, at 30, no one could withstand 3 of my strikes, at 40, was supreme overlord, at 50, abandoned the throne, and so I leave behind these 10 words..." The Sage Emperor's six generals are all around that deity rank.