The ranks of demons corresponded to their strengths.
For the world that Aidos' invaders came from:
Master Levels and Below were Low-Rank Demons.
Grandmasters and Epics were Lower and Upper Mid Rank Demons.
While Legendries and Sovereigns were High Ranks.
The Peak Rank was normally reserved for Transcendents.
However, there were special circumstances, when Sovereign Level Demons attained Peak Rank status.
In a way, these Peak Rank Sovereigns were actually more dangerous than their Transcendent counterparts.
Take the Deadly Sin Siblings for example. They were so strong that even Transcendents were wary of them.
The woman right in front of them was definitely a Sovereign, but the fact that she was Peak Rank showed she was just as nonstandard as the Deadly Sin Siblings.
