300. The Academy.
The young masters and the young ladies of the noble households were all at higher levels. Because, for the honour of their households, they were asked to get stronger than the "others" from other noble households, under this fierce, unhealthy competition amongst the noble households, the ignorant and arrogant children of such houses were forced to get stronger, no, "level up," as the master of the household had their military forces bring in the higher-ranked monsters that were beaten to the verge of death, with the thoughts of abusing the system's levelling up function to the fullest.
Then, when the monsters were killed by the young masters or the young ladies with a single stab or a slash, they,
Levelled up!
With such methods, the nobles got stronger as time passed, while the commoners with actual talent and courage were forced to stay in their houses by their commoner parents, who were scared of losing their kids.