The Imperial Guards of Celestial Realms City, whether the Ma Army or the Infantry, all come from the Outer Sect of Heaven-Piercing Palace.
The admission requirements for the Outer Sect of Heaven-Piercing Palace demand at least the Nascent Soul Realm as the lowest level.
In the Ma Army, apart from the coachmen in logistics whose cultivation level is slightly lower, anyone who didn't get in through connections has a cultivation level above the Nascent Soul Realm.
Some people stayed in Heaven-Piercing Palace for three years, yet remained at the early stage of the Nascent Soul Realm.
This is the difference in aptitude; without special opportunities, those with low aptitude find their cultivation increasingly fixated as they progress.
The lowest of the Vulture Camp is at the early Soul Ascension Stage.
After leaving Heaven-Piercing Palace, one by one they just spent their days in the Imperial Guards, having long lost their initial ambitions.
