The Sovereign Profound Realm was the highest realm that could be reached in the Profound Sky Continent, and it was the same in the Illusory Demon Realm. In the Illusory Demon Realm, the strong who had reached Sovereign Profound Realm were mostly from Demon Imperial City. Outside of Demon Imperial City, it was hard to even have one in a few thousand years. And even in Demon Imperial City, very few reached Sovereign Profound Realm. The number of Monarchs was the most important factor in determining how strong a family was.
And, being at the top of the profound cultivating world, Monarchs were also divided into different levels… even though early stage and mid stage Monarchs were both in the Sovereign Profound Realm, their power levels were worlds apart.