Because of the extreme strength Yila exhibited, along with the terrifying descriptions provided by other leaders, combined with their respectful attitudes... Satan Ye developed a significantly skewed perception of the strength of transcendent beings in the world.
First, it's worth mentioning that each of the leaders was not weak at all.
In terms of a typical RPG game, the leaders could all be considered the [strongest] subordinates of the [Demon King], equivalent to the level of the [Four Heavenly Kings] just below the final boss.
If we consider the former Demon King... who was Favignano, and treat his power as that of the [final BOSS], then the leaders could be recognized as [next to the strongest].
Unfortunately, due to Yila's appearance, Satan Ye naturally categorized Yila as the [strongest] tier, which meant the remaining leaders' statuses had to be pushed back accordingly.
But it shouldn't have been that way...